The Pennsylvania State University
The Graduate School
Harold and Inge Marcus Department of Industrial and Manufacturing Engineering
USING PRODUCT DISSECTION TO EXPOSE ENGINEERING STUDENTS TO CULTURAL ISSUES IN PRODUCT DESIGN
A Thesis in
Industrial Engineering
by
Kang Kang
2011 Kang Kang
Submitted in Partial Fulfillment of the Requirements for the Degree of
Master of Science
August 2011
ii The thesis of Kang Kang was reviewed and approved* by the following:
Timothy W. Simpson Professor of Mechanical Engineering and Industrial Engineering Thesis Advisor
Gül E. Okudan Kremer Associate Professor, Engineering Design and Industrial Engineering
Paul Griffin Peter and Angela Dal Pezzo Department Head Chair Head of the Department of Industrial Engineering
*Signatures are on file in the Graduate School
iii
ABSTRACT
With the growing use of product dissection for benchmarking purposes in industry and for engineering education purposes in academia, a systematic and practical dissection methodology and a model for dissection in education are needed. This work reviews and compares existing methodologies and based on that introduces an integrated product dissection methodology to assess product architecture and functionality. A case study is used to demonstrate the proposed methodology on two rice cookers, and cultural issues of rice cooker design are identified.
With globalization becoming an important issue, bringing the concept of global and societal issues into engineering design education is essential. Inspired by the findings of the rice cooker dissection, an experiment is conducted to test the incorporation of rice cookers into product dissection activities in the Spring 2011 offering of ME240: Product Dissection at the
Pennsylvania State University. The purpose of adding rice cookers to the appliances dissection section of the course is to expose students to the cultural issues of rice cooker design (e.g., product functions and features based on cooking and dietary needs). The students’ responses were collected and analyzed including numbers of correct responses, sketches of mechanisms and components, suggestions for improving the design, and feedback on cultural needs. The results provide a baseline for future educational evaluation.
iv TABLE OF CONTENTS
LIST OF FIGURES ...... vi
LIST OF TABLES ...... ix
ACKNOWLEDGEMENTS ...... xi
Chapter 1 Introduction to Product Dissection ...... 1
1.1 Importance of Product Dissection ...... 1 1.1.1 Applications in industry ...... 1 1.1.2 The Law and Economics ...... 3 1.2 Engineering Design Education ...... 4 1.3 The Definition of Culture and Possible Impact on Product Design ...... 5 1.4 Research Objectives ...... 7 1.5 Overview of the Thesis ...... 7
Chapter 2 Product Dissection: Definitions, Related Work and Methodologies ...... 9
2.1 Definition and Related Terms ...... 9 2.2 Comparison of Methodologies ...... 10 2.3 Methods and Tools to Support Systematic Product Dissection ...... 16 2.3.1 Customer Needs Assessment and Function Analysis ...... 16 2.3.2 Tools to Aid Dissection ...... 24 2.3.3 Product Architecture and Decomposition Tools ...... 25 2.4 Summary ...... 29
Chapter 3 A Proposed Product Dissection Methodology ...... 30
3.1 Phase I: Pre-Dissection ...... 32 3.1.1 Step 1: Investigation and Hypothesis ...... 32 3.1.2 Step 2: Dissection Plan and Preparation ...... 34 3.2 Phase II: During Dissection ...... 37 3.2.1 Step 1: Dissection of the Product to Lowest Level ...... 37 3.2.2 Step 2: Documentation of the Process of Disassembly ...... 37 3.3 Phase III: After-Dissection ...... 39 3.3.1 Step 1: Experiment with the Whole Product ...... 39 3.3.2 Step 2: Analysis and Better Understanding ...... 40 3.3.3 Step 3: Further Investigation and Analysis ...... 42 3.4 Comparison of the Existing Work and Proposed Methodology...... 43
Chapter 4 Product Dissection Case Study---Rice Cooker...... 47
4.1 Phase I: Pre-Dissection ...... 48 4.1.1 Step 1: Investigation and Hypothesis ...... 48 4.1.2 Step 2: Dissection Plan and Preparation ...... 63
v 4.2 Phase II: During-Dissection ...... 65 4.2.1 Step 1: Dissection of the Product to Lowest Level ...... 65 4.2.2 Step 2: Documentation of the Process of Disassembly ...... 66 4.3 Phase III: After-Dissection ...... 71 4.3.1 Step 1: Experiment with the Whole Product ...... 71 4.3.2 Step 2: Analysis and Better Understanding ...... 71 4.3.3 Step 3: Further Investigations and Analysis ...... 79 4.4 Conclusions ...... 86
Chapter 5 Exposing Students to the Cultural Aspects of Rice Cooker Design through Product Dissection ...... 87
5.1 Experiment Objectives ...... 87 5.2 Product Dissection at Penn State...... 89 5.3 Rice Cooker Dissection Activity ...... 90 5.4 Metrics for Evaluation...... 94 5.5 Experimented Results ...... 94 5.5.1 Summary of Correct-answer Questions ...... 95 5.4.2 Summary of Open-ended Questions...... 103 5.6 Conclusions and Suggestions for Rice Cooker Dissection Activities ...... 107 5.6.1 Conclusions ...... 108 5.6.2 Suggestions...... 108
Chapter 6 Summary and Future Work ...... 110
6.1 Summary ...... 110 6.2 Future Work ...... 111 6.2.1 Product Dissection Methodology ...... 111 6.2.2 Rice Cooker Dissection Activity ...... 112 6.2.3 Engineering Design Education Incorporating Product Dissection ...... 112
References ...... 114
Appendix A Manual and Cooking Guide ...... 123
Appendix B Dissection Documentations ...... 126
Appendix C Students’ Answers to the Assignment Question 9-11 ...... 137
vi LIST OF FIGURES
Figure 1-1. The methodology flow of the thesis ...... 8
Figure 2-1. Phases of Otto and Wood’s reverse engineering and redesign methodology [2] ...... 11
Figure 2-2. Otto and Wood's reverse engineering methodology [2] ...... 12
Figure 2-3. General phases of product dissection ...... 13
Figure 2-4. Format of a black box model [1] ...... 17
Figure 2-5. A FAST Diagram model [1]...... 18
Figure 2-6. A function model format [1] ...... 20
Figure 2-7. Functional analysis process [2] ...... 21
Figure 2-8. Basic flow classes [44] ...... 22
Figure 2-9. Basic function classes [44] ...... 23
Figure 2-10. Example FCM ...... 26
Figure 2-11. DSM Taxonomy [51] ...... 28
Figure 2-12. An example DSM [46] ...... 29
Figure 3-1. Proposed product dissection methodology ...... 31
Figure 3-2. The black box model for a rice cooker ...... 33
Figure 3-3. Rice cooker FAST Diagram ...... 34
Figure 4-1. Panasonic SR-GO6FG [52] and Aroma ARC-150SB [53] ...... 47
Figure 4-2. Aroma ARC-150SB control panel [54] ...... 49
Figure 4-3. Pot-style rice and cool-touch rice cookers [81,82] ...... 54
Figure 4-4. One-touch operation rice cooker models [82,83] ...... 54
Figure 4-5. Aroma ARC-838TC and Maxi-Matic DRC-1000B [84,85] ...... 55
Figure 4-6. Aroma ARC-150SB and Zojirushi NS-ZCC18 [86, 87] ...... 55
Figure 4-7. Zojirushi's NS-ZCC18 Neuro Fuzzy 10-cup [87] ...... 56
vii Figure 4-8. Zojirushi NP-LS10 [90] ...... 57
Figure 4-9. Philips HD4761 [91] ...... 58
Figure 4-10. Zojirushi NP-LS10 [90] ...... 58
Figure 4-11. Black box model for Panasonic SR-GO6FG ...... 59
Figure 4-12. Black box model for Aroma ARC-150SB ...... 59
Figure 4-13. FAST Diagram for Panasonic SR-GO6FG ...... 61
Figure 4-14. FAST Diagram for Aroma ARC-150SB ...... 62
Figure 4-15. Removing switch from SR-GO6FG ...... 65
Figure 4-16. Physical connections of Aroma ARC-150SB and Panasonic SR-GO6FG ...... 66
Figure 4-17. Thermostat and actuation lever of model SR-GO6FG ...... 66
Figure 4-18. Function structure for the Panasonic SR-GO6FG ...... 72
Figure 4-19. Function structure for the Aroma ARC-150SB ...... 73
Figure 4-20. Temperature sensor assembly, Panasonic SR-GO6FG ...... 81
Figure 4-21. The temperature assembly in Aroma ARC-150SB ...... 82
Figure 5-1. Framework for classifying product dissection-based activities [103] ...... 88
Figure 5-2. Summary of correct answers ...... 96
Figure 5-3. Example sketch of thermosat mechanism ...... 96
Figure 5-4. Example sketch of thermostat mechanism ...... 97
Figure 5-5. Example sketch of “keep-warm” mechanism ...... 97
Figure 5-6. Incorrect example sketch of thermostat mechanism ...... 98
Figure 5-7. Incorrect example sketch of thermostat mechanism ...... 98
Figure 5-8. Example sketch of the function of the spring ...... 99
Figure 5-9. Counts of answers to functions and component ...... 100
Figure 5-10. Example response for function to component ...... 101
Figure 5-11. Example sketch of connections ...... 102
viii Figure 5-12. Comparison of Questions 6-8 ...... 103
Figure A-1. Aroma manual [54] ...... 123
Figure A-2. Aroma cooking guide [54] ...... 124
Figure A-3. Panasonic Manual [52] ...... 125
ix LIST OF TABLES
Table 2-1. Comparison of product dissection methodologies ...... 14
Table 2-1. Comparison of product dissection methodologies (Continued) ...... 15
Table 2-2. A BOM template [1] ...... 24
Table 3-1. Dissection plan template [1] ...... 35
Table 3-2. Worksheet for choosing measurement tools [1] ...... 36
Table 3-3. Partial BOM of Aroma ARC-150SB ...... 38
Table 3-4. FCM for Panasonic SR-GO6FG ...... 41
Table 3-5. DSM for Panasonic SR-GO6FG...... 42
Table 3-6. Comparison of the exiting work and the proposed methodology ...... 44
Table 3-6. Comparison of the exiting work and the proposed methodology (Continued) ...... 45
Table 4-1. Rice cooker market segmentation ...... 52
Table 4-2. Rice cooker dissection plan ...... 63
Table 4-3. Rice cooker worksheet for choosing measurement tools ...... 64
Table 4-4. BOM for the Panasonic SR-GO6FG ...... 67
Table 4-4. BOM for the Panasonic SR-GO6FG (Continued) ...... 68
Table 4-5. BOM for the Aroma ARC-150SB ...... 69
Table 4-5. BOM for the Aroma ARC-150SB (Continued) ...... 70
Table 4-6. FCM for the Panasonic SR-GO6FG ...... 74
Table 4-7. FCM for the Aroma ARC-150SB ...... 75
Table 4-8. DSM for the Panasonic SR-GO6FG ...... 77
Table 4-9. DSM for the Aroma ARC-150SB ...... 78
Table 4-10. Comparison of key assemblies and components ...... 80
Table 4-11. Consumption of rice by country 2003/2004 [94] ...... 83
x Table 4-12. Rice varieties ...... 84
Table 4-13. Rice types ...... 85
Table 5-1. Rice cooker assignment ...... 91
Table 5-1. Rice cooker assignment (Continued) ...... 92
Table 5-2. Rice cooker models dissected in class ...... 93
Table 5-3. Table for answering Question 8...... 100
Table 5-4. Summary of students’ answers to Question 9...... 104
Table 5-5. Students’ suggestions on rice cooker design ...... 105
Table 5-6. Summary of Question 11 ...... 107
xi ACKNOWLEDGEMENTS
I would like to thank Dr. Timothy W. Simpson for reviewing my thesis and his guidance of my research. This thesis would not have been possible without the opportunities he offered.
I would also like to thank Dr. Gül E. Okudan Kremer and Dr. Paul Griffin for reviewing the thesis.
I wish to acknowledge the advice and guidance provided by Dr. Seung Ki Moon, the introduction provided by Avanti Jain, and the help from Öykü Aşıkoğlu.
I would like to show my gratitude to Tien-Kai, Lin, who is particularly supportive.
Lastly, and most importantly, I wish to thank my parents, Fengyun Li and Huaping Kang.
They offer me endless support and unconditional love.
This work was supported by a collaborative Phase II grant from the Course, Curriculum, and Laboratory Instruction (CCLI) program at the National Science Foundation (Grant Nos.
DUE-0920259, 0920047, and 0919724). Any opinions, findings, and conclusions or recommendations presented in this thesis are those of the author and do not necessarily reflect the views of the National Science Foundation.
1
Chapter 1
Introduction to Product Dissection
Product dissection, frequently referred to as product teardown in industry, is a crucial step in the process of reverse engineering and benchmarking. Otto and Wood [1] define product teardown as “the process of taking a product apart in order to understand how the company made the product succeed”. If a company has no product in the market, then product teardown can help establish a competitive baseline. For educational purposes, students can apply a product teardown process “to dissect, deduce and understand how a product was designed” [2] (pp. 231).
1.1 Importance of Product Dissection
Reverse engineering has become a common practice for enterprises to evaluate competing products and also to optimize their own designs. At the same time, it is regarded as an effective approach for teaching engineering design methods, since it “represents a bridge between theory and reality” [3] (pp. 363).
1.1.1 Applications in industry
Reverse engineering is frequently used as a benchmarking method in industry. For example, General Motor’s Vehicle Assessment and Benchmarking Activity Center [4] use a standard teardown process that takes about 6 weeks to fully dissect one of its competitor’s vehicles; it dissects and analyzes nearly 40 vehicles each year [4]. General Motors uses
2 information gathered from dissection to improve manufacturing and reduce costs. Similarly, Ford has competitive intelligence teams in their Automotive Strategy and Corporate Strategy Offices, and DaimlerChrysler disassembles competitors’ products within their Competitive Teardown
Operations Department [5]. To reduce the cost and resources used in the teardown process, automotive manufactures also outsource independent product assessment companies to perform contract teardown and measurements [6].
Reverse engineering or benchmarking is also used to improve manufacturing companies’ product lines. For instance, Whirlpool’s suppliers have the opportunity to disassemble Whirlpool products in the Supplier Innovation Challenge [7]. The goal is to identify ways to reduce costs, improve quality, and create innovative ideas for Whirlpool.
Suppliers have also adopted reverse engineering as a strategy to provide better service for their customers. Automobile suppliers such as Lear, Johnson Controls, TRW, and Motorola conduct competitive intelligence activities using teardown rooms, competitor product databases and part performance analyses [5]. Dofasco, a steel producer and a supplier of the appliance original equipment manufacturers, has spent many years perfecting its appliance teardown process since its customers were demanding cost savings measures [8]. Similarly, Henkel offers its customer a teardown service that identifies opportunities to substitute adhesives for mechanical fastening methods to reduce costs [9]. Suppliers like Dofasco and Henkel realized that providing teardown services with cost reduction ideas and innovative solutions is a valuable customer service that can distinguish them from other suppliers [10].
Reverse engineering is also a common practice in the electronics and computer software industries. In the computer and software industry, two common forms of software reverse engineering, which are decompilation and disassembly of object code, are frequently used [12].
3 1.1.2 The Law and Economics
In the 1970s and 1980s, some states forbid using direct molding process to reverse- engineer boat hulls [13]. However, reverse engineering has been endorsed by lawyers and economists as an appropriate way to obtain information about the design and manufacturing of products, even if the result may draw customers away from the initial maker of the product. It is
“generally a lawful way to acquire know-how about manufactured products” [14] (pp. 1582).
However, controversies still arise now and then about the legality of reverse engineering especially in the semiconductor and computer software industries. In 1998, Congress outlawed the reverse engineering of technical protections for digital versions of copyrighted works. The law prohibited the creation and distribution of tools for reverse engineering of digital versions of copyrighted works as well as the disclosure of information obtained in the course of lawful reverse engineering [14].
Although controversies and questions have arisen, the law favors reverse engineering in traditional manufacturing as well as in the semiconductor and computer software industry.
Research shows favoring reverse engineering is economically more beneficial. Samuelson and
Scotchmer [14] noted that since reverse engineering is generally costly, time-consuming, it already protects most innovators. Thus a right to reverse-engineer “has a salutary effect on price competition and on the dissemination of know-how that can lead to new and improved products”
[14] (pp. 1590).
4 1.2 Engineering Design Education
For the last two decades, product dissection has been applied in engineering design education and has been used in a variety of ways to engage students in engineering courses [15].
The first formal course in product dissection is ME 99 Mechanical Dissection at Stanford in 1991
[16]. The goal of the course is not only to allow students to dissect an industrial product but also to help students understand the issues involved in bringing a design from concept to reality [3]. A resurgence of dissection activities in engineering classrooms have followed, aimed at enhancing engineering design education.
Dissection activities have been integrated into courses in a variety of different institutions and universities at both the undergraduate and graduate levels. Garrett [17] at Grand Valley State
University developed a course for senior students, Design for Disassembly and Design for
Recyclability Techniques, which uses dissection of mechanical devices (e.g., a hand-held electric mixer and a toaster) for teaching [17]. Gabriele [18] of Rensselaer Polytechnic Institute has also developed a course using reverse engineering methods to teach and let students experience the redesign process [18]. Reverse engineering was used to restructure the design methods courses at
UT-Austin, MIT, and USAFA [3]. A product dissection course was also developed as part of the
Manufacturing Engineering Education Partnership between Penn State University, the University of Washington, and the University of Puerto Rico-Mayaguez [15].
Product dissection has successfully helped students identify relationships between engineering fundamentals [15]. It has also shown to be effective in improving students’ understanding of platform commonality [15] in a mechanical engineering and industrial engineering graduate-level course on product family design at Penn State University. The course evaluations of six design methods courses at UT-Austin, MIT and USAFA were found to be well above the average of college of engineering reviews because of the reverse engineering activities
5 students performed [3]. It is also noted by Wood and Jensen [3] that through reverse engineering projects, students can have more concrete experiences to help learn design methods. Reverse engineering tools have proven to be beneficial in teaching by arousing students’ interest and bringing enjoyment to the classroom and helping create self-motivated learning.
Although numerous engineering courses in undergraduate-level education incorporate product dissection activities and receive positive reviews, the majority of these activities tend to focus on the technological aspects of the product [19]. With globalization, environmental resource limitations, economic recession, and societal concerns creating challenges for industry and product development, it is important to provide exposure to these topics in engineering design education. While most courses emphasize the function and architecture of a product through dissection activities, one exception is the dissection of single-use cameras to discuss the recycling and design for reuse issues in The Pennsylvania State University [19]. The objective in this thesis is to expand on these dissection activities to address design concerns related to the cultural impact of product design as described next.
1.3 The Definition of Culture and Its Impact on Product Design
The definition of culture varies widely in different fields of study. Damen [20] defines culture as "learned and shared human patterns or models for living; day-to-day living patterns, these patterns and models pervade all aspects of human social interaction. Culture is mankind's primary adaptive mechanism" (pp. 367). Hofstede [21] defines culture as "The collective programming of the mind which distinguishes the members of one category of people from another" (pp. 51). Lederach [22] states that “"Culture is the shared knowledge and schemes created by a set of people for perceiving, interpreting, expressing, and responding to the social realities around them" (pp. 9). The term “cultural norm” is defined by Williams [23] as “a
6 specific prescription of the course that action should (is supposed to) follow in a given situation…for a whole group or society” (pp. 24-25).
Based on these definitions, Tse, et al. [24] raise the issue: “does culture Matter?”. Their work studies executives’ choice in international marketing, and their results show that, using four simulated international marketing situations with executives from China, Hong Kong, and
Canada, cultural norms do impact marketing decision-making and risk adjustment. Kim and Lee
[25] identify that cultural differences to some extent affect mobile phone interface design in terms of icon recognition according the level of abstraction. Erickson, et al. [26] found that studies reported in the marketing literature confirmed the importance and impact of cultural influence on consumer behavior.
Among the few who address issues related to cultural and social influences, McCracken
[27] points out that cultural and social forces shape product preferences. Alexander [28] argues that cultural norms are particularly important regarding design since cultural norms tend to overwhelm one’s inner feelings and individual preferences. Reingen, et al. [29] argue that customers in different market segments can have substantial differences in taste due to their specific associations with groups or subcultures, and thus marketing and design should recognize these potential impacts due to social class, age, region, and ethnic subcultures when creating design preferences. With the potential impact that culture has on marketing and design, the idea of exposing students to these cultural issues in product design becomes an important issue to address in engineering education as discussed in the next section.
7 1.4 Research Objectives
One of the objectives in this thesis is to review and compare existing methodologies, and based on that, create a product dissection methodology that is suitable for educational purposes.
After the methodology is introduced, two rice cooker models are dissected to demonstrate the three phases of the proposed methodology: (I) before-dissection phase of investigation and preparation, (II) during-dissection phase of dissection and documentation, and (III) the after- dissection phase of analysis. The results of the dissection shows differences in the functionalities and product architectures of the two rice cookers and reveals some of the cultural issues of rice cooker design.
Globalization and social concerns are creating challenges for engineers in both product development and redesign process. However, as discussed in Section 1.2 most of the product dissection activities in education fail to highlight the global, environmental, economic and societal issues that influence product design and development. The attempt to expose students to cultural issues in product design motivated an experiment of incorporating rice cookers in the product dissection activities in the Spring 2011 ME240: Product Dissection course at Penn State.
The results of the experiment summarized the percentage of correct answers and responses to cultural issues of the rice cooker assignment. The objective is to create a baseline for next year’s dissection activity or related educational activities that aim to expose students to the cultural impact of product design.
1.5 Overview of the Thesis and Methodology Flow
This chapter introduces the importance of product dissection to academia and industry, and the law and economic aspects of reverse engineering. The background and motivation for the
8 work is also presented. Chapter 2 summarizes and compares product dissection methodologies and reviews the methods and tools that aid the process of dissection and analysis. Based on the summary of methodologies, an integrated product dissection methodology, intended for educational use, is introduced in Chapter 3. Two rice cookers are dissected following the proposed methodology, and a case study is presented in Chapter 4. Through the dissection, the cultural impacts of rice cooker design are identified and further investigated. An experiment inspired by the cultural impact is conducted to test the use of rice cookers in appliance dissection activities. The details and results of the experiment are provided in Chapter 5. Chapter 6 summarizes the work and discusses future work.
A roadmap for the thesis is shown in Figure 3-5.
Chapter 4 Chapter 5
Chapter 3 •Case study to •Prepare Chapter 2 demonstrate the assignment and •Integrate a proposed rice cooker methodolgoy mothodology dissection •Review •Compare the •Investigation in activities based methodologies existing work cultrual impacts on the cast study and tools and the •The investigations •Collect and proposed and findings are the summarize methodology preparation for the responses of in-class dissection students activity •Provide suggestions for future work
Figure 1-1. The methodology flow of the thesis
9 Chapter 2
Product Dissection: Definitions, Related Work and Methodologies
Product dissection is often used by firms to evaluate competing products and also to optimize or redesign their current product offerings. The following sections review the definitions of product dissection and reverse engineering, several product dissection methodologies, and the methods and tools applicable to the decomposition of products.
2.1 Definition and Related Terms
Product dissection is part of any reverse engineering process. Product dissection is listed as the second step in Otto and Wood’s [1,2] reverse engineering methodology, which initiates the redesign process. Combined with benchmarking analysis, product dissection can improve
“product design, produce superior performance and product quality” [30] (pp. 1317).
Reverse engineering, as defined by Otto and Wood [1,2], “initiates the redesign process wherein a product is predicted, observed, disassembled, analyzed, tested, ‘experienced’, and documented in terms of its functionality, form, physical principles, manufacturability, and assemblability” (pp. 226). A broader definition of reverse engineering is “a process of extracting know-how or knowledge from a human-made artifact” [14] (pp. 1577).
The purpose of reverse engineering is generally to evaluate the parts and the technology used in production by disassembling an existing product. Ingle [31] describes the objective of reverse engineering as finding the technical support needed to update older designs. Otto and
Wood [2] further define it as a process to “fully understand and represent the current instantiation of a product” (pp. 226).
10 Product benchmarking is defined by Harrington [32] as “a systematic way to identify, understand, and creatively evolve superior, products, services, designs, equipment, processes, and practices to improve [an] organization’s real performance”(pp. 202). Product benchmarking can provide ideas for both product and process design [33,34], in which organizations evaluate various aspects of their products and/or processes in relation to competitors or best practices.
2.2 Comparison of Methodologies
Although product dissection or product teardown is commonly employed in industry and in engineering education, little research addresses methodologies for effective dissection. Without such a methodology, information captured or data collected during the dissection process may not be consistent, and more importantly, a thorough assessment of the target product’s success may not be possible.
Among those who have developed systematic approaches for reverse engineering,
Whitney [35] outlines steps to disassemble a product and gather data to help teach concepts such as product architecture and design for assembly. Ingle [31] provides detailed directions for product dissection. Otto and Wood [2] use reverse engineering as the first phase of a proposed redesign process (see Figure 2-1), and the intent of the first phase is two-fold [1,2]. The first phase is to study customer needs and hypothesize product functionality, product components, and physical principles. The second phase is to fully disassemble the product (see Figure 2-2). In their book [1], they further divide the process into three steps, adding “competitive benchmarking” as the last step. The first step is to treat the product as a “black box” and study it regarding customer needs, hypothesized functionality, product components and physical principles. The second step is to experience the actual product regarding both function and form. Finally, Steva [11]
11 developed a product dissection methodology for dissecting a group of products and added analysis methods for product family and product platform design.
Figure 2-1. Phases of Otto and Wood’s reverse engineering and redesign methodology [2]
12
Figure 2-2. Otto and Wood's reverse engineering methodology [2]
Steva [11] summarized the objectives of these methodologies as:
1) Define product functionality,
2) Assess design for assembly,
3) Uncover the rationale behind the product’s design, and
4) Determine the manufacturing cost of the product.
The differences between methodologies given by Ingle [31], Otto and Wood [1,2], Whitney [35], and Ulrich and Pearson [36] stem primarily from the level of detail given and the end use of the data being collected. Table 2-1 provides a summary and comparison of the work by Ingle [31],
Otto and Wood [1,2], Whitney [35], Ulrich and Pearson [36], and Steva [11].
13 Despite the differences in level of detail, product dissection methodologies can be generally divided into three phases as indicated in Figure 2-3. The first phase is usually a preparation for dissection, and the second phase is the actual dissection. The third phase involves analysis and benchmarking, aiming at optimizing the dissection process.
Pre-disassembly Before preparation
The teardown and During experimentation process
Following up analysis and After benchmarking
Figure 2-3. General phases of product dissection
14
Table 2-1. Comparison of product dissection methodologies
Phase Steps Sub-steps/Tools Source Pre- List the design issues Otto and Wood [1] disassembly Use/experience the Otto and Wood [2], Steva [11] product Hypothesize the Black box model Otto and Wood [1,2], Steva functions [11] Gather list of Function structure and Otto and Wood [1,2] customer needs Function modeling Examine the Otto and Wood [1] distribution and Installation Plan product Determine data needed for Otto and Wood [1,2], Steva disassembly collection [11] Measurement selection Otto and Wood [1,2] Tools selection Otto and Wood [1,2] Disassembly plan Otto and Wood [1,2], Ingle [31] Dissection Dissect the product Identify physical Otto and Wood [1,2], Steva Process to the lowest connections before [11] desirable level removing component Remove one component Steva [11] at a time, photograph components before removal Take measurements on Otto and Wood [1,2] parts and assemblies to complete the data sheet Document the order Organize assemblies, Otto and Wood [1,2], Whitney of disassembly subassemblies and [35], Steva [11] components hierarchically Label removed Otto and Wood [1,2], Whitney components [35], Ingle [21], Ulrich and Pearson [36], Steva [11] List access direction Otto and Wood [1,2] List orientation of product Otto and Wood [1,2] Acknowledge/document Otto and Wood [1,2] expected permanent deformation
15 Table 2-1. Comparison of product dissection methodologies (Continued)
Phase Steps Sub-steps/Tools Source List the tool usage Otto and Wood [1,2], Whitney [35] Take photos of Otto and Wood [1], Steva disassembly [11] Execute Subtract and Otto and Wood [2] Operate Procedure (SOP) Experiment with Identify main function of Whitney [35] product components assemblies, sub- (Non-SOP) assemblies and components Identify degree of Whitney [35] freedom (DOF) Understand inclusion of Otto and Wood [1,2], parts/features Whitney [35] Understand Otto and Wood [1,2], assemblability of the Whitney [35], Ingle [31], product Ulrich & Pearson [36] Create BOM, BOM, exploded view, Otto and Wood [2], Ulrich exploded view, and parameter List and Pearson [36] parameter list Experiment with Otto and Wood [1,2] overall product Post- Function analysis Energy flow diagrams, Otto and Wood [1,2] Disassembly force flow analysis. Analysis Create refined Otto and Wood [1,2] function structure of actual product Create morphological Otto and Wood [2] matrix Create function Otto and Wood [2] sharing and comparability Transform to House of Quality Otto and Wood [2] engineering specs & Metrics (QFD) Execute platform Bill of materials platform Steva [11] identification identification methodologies methodology (BOM- PIM) Function based platform Steva [11] identification methodology (FCN-PIM)
16 2.3 Methods and Tools to Support Systematic Product Dissection
Several methods and tools are available in the literature to assist in the product development process, and they can be used to aid product dissection activities and analysis. The following sections review several methods and tools applicable to assist systematic product dissection, represent the product architecture, and facilitate product decomposition.
2.3.1 Customer Needs Assessment and Function Analysis
Customer needs assessment is often carried out as the first step of the design process. The intent of gathering customer needs in a design (or redesign) process is usually to help clarify the product domain, form the product design specifications, and identify product functions. Otto and
Wood [2] note a statistical representation of customer needs is the desired result, and there are various methods of gathering lists of customer needs [1, 37-38]. They also classify customer needs into three categories: (1) direct or latent, (2) constant or variable, and (3) general or niche.
Once all the needs are identified, they can be weighted or ranked and related to engineering specifications using Quality Function Deployment [38].
The best way to identify the basic function of the product is to build a “black box” model.
The black box model treats the product being dissected as a “black box” and determines the input and output flows of materials, energy, and signals and the global function of the product [2]. The intent of building such a black box model is to understand the overall product function without actually dissecting the product down. Otto and Wood [1,2] note that the black box model provides an initial mapping of customer needs into understanding of a design.
To build a black box model, the first step is to model the product abstractly with three types of inputs and outputs, which are material, energy, and information flow. Otto and Wood [2]
17 note that those three flows are sufficient to describe a product or a technical system. Figure 2-4 provides a format of a black box model with material, energy, and information flow.
Energy Product Energy Represented as a Material Material Functional System Information Information
Figure 2-4. Format of a black box model [1]
The Function Analysis System Technique (FAST) [39] reveals the arrangement of functional elements and is used to define, analyze, and understand product functions [1]. It is used to display a product’s functions in a sequence and hierarchy. An example FAST Diagram model is provided by Otto and Wood [1] in Figure 2-5. It is a top-down approach [1], which starts with the overall function of the product and then decomposes it. It is often adopted as an approach to develop new product systems and architectures. However, when applied before the dissection to predict the functions of a product, a FAST Diagram can provide a clear structure of the basic function and sub-functions.
All the functions of the product should be brainstormed by asking the question “what the product does”. During this process, it is obvious that the functions brainstormed have different levels of importance. The most important function can be selected as the “overall product function” or the “basic function” in Figure 2-5.
18
Figure 2-5. A FAST Diagram model [1]
The steps for constructing a FAST Diagram are as follows [1]:
1) Construct two dashed vertical lines to define the scope of the product objective.
2) Place the basic function on the right of the left-hand scope line. A higher order function,
which can answer the question “Why the basic function is performed”, is placed on the
left.
3) Generate functions to the right of the basic function by asking “how is this function
achieved” and then connect these functions to define the critical path.
4) Generate the remaining secondary functions by placing them under the related basic and
secondary functions.
19 5) State the objective of the product above the basic function and add one-time or all-time
functions as well.
After the dissection of the product, the functional relationships must be carefully determined. Functional analysis can be associated with customer needs and further identify areas for potential product improvements [1]. After disassembly, a more detailed or even revised functional analysis should be conducted based on the initial function structure prediction.
Identifying and evaluating these function structures are very important for benchmarking purposes. Related terms of functional analysis are explicitly defined in [40]:
1) Product function: The general input/output relationship of a product, with the purpose of
performing an overall task. Product function is usually expressed in verb-objected form,
e.g., active verb-noun pair such as increase pressure.
2) Sub-function: A description of part of a product’s overall task (i.e., product function) and
usually decomposed from it. Sub-functions usually represent the more elementary tasks
of the product and are stated in verb-object form as product function.
3) Functional model: A description of a product or process in terms of the elementary
functions that are required to achieve the overall task or function.
4) Function structure: A graphical form of a functional model. The overall function structure
is represented by a collection of sub-functions connected by the flow(s) on which they
operate.
5) Functional basis: A design language consisting of a set of functions and a set of flows
that are used to form a sub-function.
6) Flow: A change in material, energy, or information with respect to time.
20 The function model or function structure is a representation of an electromechanical system, consisting of the input and output of the system and internal sub-functions within the system [41]. It is defined as an input-output model that maps energy, material, and information flows to a transformed and desired form [42,43]. A functional model format is provided in Figure
2-6. With three types of flows: energy, material, and signal, the compatible combination of sub- functions into the overall function produces a function structure. There are usually a number of function structures that will satisfy the overall functional requirements; thus, these sub-function structures are schematically networked together to form an overall function structure.
Figure 2-6. A function model format [1]
Otto and Wood [1] provide a process (see Figure 2-7) and also gives the steps to develop function structures. The steps of a function structure modeling process are as follows [1]:
1) Develop process descriptions as activity diagrams. The activity diagram is defined as a
network layout of sequential and parallel tasks carried out by the user.
2) Formulate sub-functions through task listing. In this step, primary flows (energy,
material, and information) associated with each function and sub-function should be
identified. Flow classes and basic flows are provided in Figure 2-8. After primary flows
are identified, a sequence of sub-functions and specific user operations on that flow
21 should also be identified. A summary of function classes and basic functions is given in
Figure 2-9.
3) Aggregate sub-functions into a refined function structure.
4) Validate the functional decomposition.
Generate Function Create Hierarchy Aggregate Sub- Create Define Process functions, Alternative Black Description Refine Function Box Create Function Structures Model Task Structure Listing
Label/Check Flows
Interaction
Figure 2-7. Functional analysis process [2]
22
Figure 2-8. Basic flow classes [44]
23
Figure 2-9. Basic function classes [44]
24 2.3.2 Tools to Aid Dissection
The order of disassembly, tool usage, and measurements should be documented properly during dissection. Each component is labeled and added to a bill-of-materials (BOM) [1,2] as it is removed. The BOM [1,2] documents components by subassembly and contains data of each component’s material, mass, quantity, color, classification, measurement, and function. It is also essential to document the way components are connected to each other, i.e., the flows in the product and also the dependencies between components [35]. A BOM template is provided in
Table 2-2. Another tool to aid the documentation of disassembly is an exploded view, which shows the relationship or order of assembly of the components. Along with the BOM, all assemblies, sub-assemblies, and parts in the order of their original assembly can be documented.
Table 2-2. A BOM template [1]
Bill of Materials Project Name
Engineer(s) Date
Functional Analysis DFM Cost Analysis
Part # Part Name Qty. Function Flows In Flows Out Process Manuf. Dimensions Mass Material Finish Variables Other
25 As the product is dissembled, it is important to understand the function of each component. The Subtract-and-Operate Procedure (SOP) is a five-step method aimed at exposing redundant components in an assembly or subassembly through the identification of each component [45]. Otto and Wood [1,2] suggest using SOP to support the teardown process to uncover the functions of subsystems and components. They outline the steps of SOP as follows:
1) Disassemble one component of the assembly (Subtract)
2) Operate the system through its full range (Operate)
3) Analyze the effect of removing the component through visual inspection or
measurements
4) Deduce the component’s function
5) Replace the component; repeat for all parts in the assemblies and subassemblies
All the measurements and findings of SOP can be compared to the BOM and updated to create a
SOP table that records the part number, part description, and the effect of removing the component.
2.3.3 Product Architecture and Decomposition Tools
Ulrich and Eppinger [33] define product architecture as “the scheme by which the functional elements of the product are arranged into physical chunks and by which the chunks interact”. One of the objectives of product dissection is to understand the product architecture.
Function structures (see Section 2.3.1), the Design Structure Matrix (DSM), and the Function-
Component Matrix (FCM) are tools to support the analysis of product architecture after dissection. Function structures or functional diagrams reveal the arrangement of functional elements [11]. A FCM represents the mapping from functional to physical components [11]. A
26 DSM addresses the specifications of the interfaces among interacting physical components [46].
FCM and DSM are described briefly in the following paragraphs.
A B C D E F G H
I
Component Component Component Component Component Component Component Component Component Component Function 1 1 1 1 1 Function 2 1 1 Function 3 1 1 1 Function 4 1 1 Function 5 1 Function 6 1 1 Function 7 1 1
Figure 2-10. Example FCM
A Function-Component Matrix (FCM) provides a mapping between product components and sub-functions [47]. It helps to relate product components with sub-functions and thus provides a detailed understanding of product functionality. An example FCM is shown in Figure
2-10. It is constructed by listing all of a product’s sub-functions in the first column of the matrix while listing all of the components in the first row. A “1” in a cell indicates that the corresponding component performs the corresponding sub-function, or in reverse, a sub-function is realized through a specific component. A “0” or blank in a cell indicates that there is no relationship between the corresponding component and the sub-function. Repeated sub-functions, which occur more than once in the product, are often consolidated into a single column [47].
The Design (or Dependency) Structure Matrix (DSM) is defined by Sharman and Yassine
[48] as “an information-modeling tool capable of representing important system (or task) relationship in order to determine an appropriate arrangement (or sequence) for the system (or project)”. DSMs are useful in a number of domains; their use in both research and industrial
27 practice blossomed in the 1990s [46]. DSMs capture the relationships between components in a system in a compact format [46], and they can model interdependencies between design objectives parameters [49]. Thus, they have become a popular analysis tool for system modeling, especially for the purposes of decomposition and integration.
A DSM can be manipulated to tailor the process structure and minimize guessing and feedback loops. For project management purposes, tasks identified by the DSM define when and where project teams need to interact during the design process [50]. There are four different types of DSM [51] applications, and Figure 2-11 shows the relationship between them.
1) Component-based or Architecture DSM: Modeling system architectures, it is based on
components and/or subsystems and their relationships.
2) Team-based or Organization DSM: Modeling organization structures, it is based on
people and/or equations, subroutine parameter exchanges, etc.
3) Activity-based or Schedule DSM: Modeling processes and activity networks, it is based
on activities and the information flow and other dependencies.
4) Parameter-Based or Low-level Schedule DSM: Modeling low-level relationships between
design decisions and parameters, systems of equations, subroutine parameter exchanges,
etc.
28
DSMs
Static Time-based
Component- Team-based Activity- Parameter- based DSM DSM based DSM based DSM
Figure 2-11. DSM Taxonomy [51]
In a component-based DSM, the first column and first row of a DSM indicates each
component in a product. The cells of the DSM correspond to the interactions between
components in a product [48]. It is limited to physical connections between components and
either spatial or material interactions [51]. Thus, the component-based DSM is always a square
matrix with identical row and column labels, and it is symmetric along the diagonal.
An example of a component-based DSM is shown in Figure 2-12 [46]. The first column and first row indicates each component in a product. Reading down a column reveals input sources, while reading across a row indicated output sinks. For example, component B provides something to component A, C, D, F, H, and I, and it depends on something from elements C, D,
F, and H. The cells on the diagonal have no physical meaning.
29
A B C D E F G H I Component A A 1 1 1 1 1 Component B 1 B 1 1 1 1 Component C 1 1 C 1 1 1 1 Component D 1 1 D 1 1 1 Component E 1 1 1 E 1 1 1 Component F 1 1 F Component G 1 1 G Component H 1 1 1 1 H Component I 1 1 1 I
Figure 2-12. An example DSM [46]
2.4 Summary
This chapter reviews the definitions of product dissection and reverse engineering. A comparison of product dissection methodologies highlights the differences between them. Finally, methods and tools that are applicable to the decomposition of products are introduced. Based on the comparison of the existing methodologies and the review of methods and tools, an integrated product dissection methodology to assess product architecture and functionality is introduced in the next chapter.
30 Chapter 3
A Proposed Product Dissection Methodology
In this thesis, a new product dissection methodology is developed by synthesizing the work of Otto and Wood [1,2], Whitney [35], Ingle [31], Ulrich and Pearson [36], and Steva [11].
This new methodology focuses on the analysis on product functionality and the understanding of product architecture and is intended for educational purposes. The phases of the proposed methodology are listed in Figure 3-1. This proposed methodology has three phases, which are before-dissection (see Section 3.1), during-dissection (see section 3.2), and after-dissection (see
Section 3.3). Each phase has different purposes and integrates tools and methods to support a systematic planning, dissection, and analysis process.
31
1. Investigation and Hypothesis a. Conduct customer needs assessment and benchmarking of the market b. Examine the product of its features, power, make and distribution c. Predict the function of the product 1. Generate “black box model” Phase I 2. Generate FAST Diagram 2. Dissection Plan and Preparation a. Develop dissection plan template Pre-Dissection b. Determine data needs to be collected c. Select measurement tools, set units of measure d. Gather necessary tools
1. Dissection of the Product to Lowest Level a. Document physical connections of the components, sketch if necessary b. Dissect and label each components Phase II c. Remove one component of a time d. Use SOP to better understand the function of certain component During- e. Photograph assembly before and after component removal Dissection 2. Documentation of the Process of Disassembly a. Organize assemblies, subassemblies and components hierarchically [11] b. Document tool usage and the order of assembly c. Label and record components and measurements on BOM d. Draw exploded view of the product
1. Experiment with the Whole Product a. Reassemble the product and examine the operation 2. Analysis and Better Understanding Phase III a. Create actual function structure b. Develop DSM to identify physical connections of components After-Dissection c. Develop FCM to map connections between functions and components 3. Further Investigations and Analysis
Figure 3-1. Proposed product dissection methodology
ii
3.1 Phase I: Pre-Dissection
The purpose in this phase of the process is to understand the product, its market, hypothesize its function, and plan for the actual dissection activity. After benchmarking the market and gathering customer needs, inspection of the product’s features, power, make, and distribution should be conducted and followed by prediction of its functions. The final step of
Phase I is the preparation of a disassembly plan. More details on each step follow.
3.1.1 Step 1: Investigation and Hypothesis
Aside from the preparation of a disassembly plan, analysis of intended customer needs and the functionality of the product are essential. The goal in this particular step of product dissection is to prepare for “necessary investigation, hypotheses and predictions for a successful product evaluation” [2] (pp. 230).
Customer needs assessment and benchmarking of other products in the market are essential in this step, since customer needs and market information provide insight into the product functionality and the criteria for the product’s success. Various methods of customer needs assessment exist, depending on the resources and time available, e.g., Voice of the
Customer [1, 37], interviews, questionnaires and focus groups survey. An inspection of the product’s features, power, make, and distribution should be conducted afterwards.
A black box model (see Section 2.1.1) can be generated to hypothesize the general function of the product. Figure 3-2 illustrates an example black box model for a basic rice cooker.
The primary function of the rice cooker is to “cook rice”. For a rice cooker, the system must convert power (e.g., 120V 60Hz) into heating. After the information of human input (e.g.,
33 pushing the “cook” button), the rice cooker must notify the user of the completion of cooking and vent the steam generated during the cooking process.
Figure 3-2. The black box model for a rice cooker
A FAST Diagram should be generated next to hypothesize the critical function path and how functions relate to one another. An example of a FAST Diagram a rice cooker is in Figure 3-
3. The basic function of a rice cooker is to “ cook rice”, and once this basic function is identified, all the other functions that a rice cooker performs, which are sensing the temperature, channeling heat, etc., are subordinate to the basic “cook rice” function. Meanwhile, the all-time function of the rice cooker is to create aesthetic appeal, and the one-time function is to vent steam. The unwanted functions of a rice cooker are the heat conducted to the housing and the steam generated during cooking.
34
Figure 3-3. Rice cooker FAST Diagram
3.1.2 Step 2: Dissection Plan and Preparation
Prior to dissection, a detailed disassembly or dissection plan is critical. A good dissection plan could positively aid the later analysis and also provides documentation for other dissection activities. Thus, before dissecting the product, several aspects should be considered such as: data to be collected, necessary tools and measurements, level of detail of disassembly, template for data capture, etc.
A dissection plan should list the expected order of disassembly, orientation of the product, tool usage, measurement selection, access direction, and any expected deformation that may be caused by dissection. This plan serves as a means for assessing the assemblability of the
35 product and a means for returning the product to its original form [2]. A template for a dissection plan is given in Table 3-1, and a measurement selection worksheet is provided in Table 3-2.
Table 3-1. Dissection plan template [1]
Product Disassembly Project Name
Engineer(s): Date:
Known Desired Information:
Disassembly Plan: Step Task Needed Tools
Measurements:
Comparison with Predictions: * Could be components, features, physics, functions
ii
Table 3-2. Worksheet for choosing measurement tools [1]
Related Functions (s):
Measurement: Flow: Units: Range:
*Determine accuracy form actual products by looking at resolution between products during benchmarking and target values
Measurements: Sketches:
Current Devices: Range Accuracy Measurements Functions Cost Device A Device B
Options:
*Select devices to cover entire range and measurements. Use other issues to help decide between possible devices
Design Issues: Calibration Dynamic Recorder Safety Mass Size Ease of Reliability ND Other Use Time (sec) Time (sec) Type (1 – 5) Kg Inch Time (1 – 5) (1 – 5) - (sec) A B C
ii
3.2 Phase II: During Dissection
In this phase, products are actually dissected, and the process of dissection should be properly documented in the form of sketches, photos, or tables.
3.2.1 Step 1: Dissection of the Product to Lowest Level
The first step in this phase is to dissect the product to the lowest possible level. In this step, one component should be removed at a time. Each component should be labeled and measured, and the connections to other components should be documented. SOP (see Section
2.3.2) could help identify the function of each component. Photographs of the assembly before and after component removal could help document the physical connections, and photographs also work better for documentation of special joints and mechanisms.
3.2.2 Step 2: Documentation of the Process of Disassembly
The next step in Phase II is to document the process of disassembly. While dissecting the product, assemblies, subassemblies, and components should be organized hierarchically. Tool usage and the order of the assembly should be documented, and all the measurements and components should be documented in a BOM. An example BOM of a rice cooker is provided in
Table 3-3. The BOM is arranged by assemblies and numbered from A1. The quantity, function, mass, material, manufacturing process, and dimensions of each component are recorded.
ii
Table 3-3. Partial BOM of Aroma ARC-150SB
Material List Panasonic SR-GO6FG Part # Part Name QTY Function Mass Material Manufacturing Dimensions (g) Process (mm) Rice Cooker A 1 Case Assembly 1 Case 1 Indicates the functions and Steel, Forming, Radius 132, options Plastic Molding Height 206 2 Outer Control Panel 1 Provide options and show N/A Plastic Molding Height 110, status Length 90 3 Condensation Collector 1 Collect condensed steam 13.8 Plastic Molding 12x61x85 4 Condensation Collector 1 Removable and clean 13.2 Plastic Molding 21x70x51 Cover
A 2 Lid Assembly 5 Lid with Handle 1 With Release button Plastic Molding Radius 133 6 Steam Vent 1 Vent out excess steam 3.18 Plastic Molding 7 Rubber Seal 1 Seal the lid with body Rubber
A 3 Central Control Assembly 8 Inner Control Panel 1 Receive chosen functions 40.4 83x58 and connect with control board 9 Control Board 1 Control cooking time and 92.3 101.5x61 temperature 10 Control Board Cover 1 Fix control boards to Case 54.6 Plastic Molding 120x62x64
ii
After the product is dissected and the BOM and exploded views are generated, identifying each part, sub-assembly, and assembly is essential for conducting further Design for
Assembly analysis. Every feature of a part and how it functions should be identified to help understand the product architecture and product functionality. After all these analysis, the product is reassembled, and the entire product is tested as an assembly [1,2].
3.3 Phase III: After-Dissection
The purpose of this after-dissection phase is to describe the product architecture in terms of function and form and the mapping between functions and components. Another purpose of this phase is to better understand the rationale behind a design with the help of some tools.
3.3.1 Step 1: Experiment with the Whole Product
After dissection, the product should be reassembled and tested as a whole. The documentation during dissection could aid the reassembling process. After the product is reassembled, the operation of the product should be examined to test if the product works properly. This step ensures the correct documentation and the understanding of the physical connections of all the components.
40 3.3.2 Step 2: Analysis and Better Understanding
Before the product is dissected, functions of the product are hypothesized through a black box model and a FAST Diagram. After dissection and the use of SOP, some predicted functions might be revised or extended. The actual function structure is generated based upon functions identified during dissection. A function structure for a rice cooker is provided as an example in
Figure 3-4.
Figure 3-4. Function structure of Panasonic SR-GO6FG
The Function Component Matrix captures the relationships between functions and components. The information needed in a FCM can be obtained from the SOP table, which
41 records the function of each component. An example FCM of a rice cooker is provided in Table
3-5.
Table 3-4. FCM for Panasonic SR-GO6FG
Actuation lever Actuation
FCM of Panasonic SR- GO6FG ousing
Status Light Status Pot Inner Plate Heating Element Heating Cover Bottom Lid Assembly Temp Sensor H Outer Panel Cover Light Status Switch Plug Cord Handle Spring Connect to Electricity 1 Switch Power On/Off 1 1 1 Convert Electricity to Heat 1 Chanel Heat 1 1 Conduct Heat 1 Sense Heat 1 1 Indicate Cooking Status 1 1 1 Transmit to User 1 1 Cleanable Inner face 1 Non-Stick Surface 1 Cool-touch 1 1
After creating the actual function structure for the dissected product, a component-based
DSM can be generated to capture the connections between components. The information needed to create the DSM can be gathered from the BOM, documentation, and photos from the dissection. An example DSM of a rice cooker is provided in Table 3-4.
42
Table 3-5. DSM for Panasonic SR-GO6FG
DSM of Panasonic SR-GO6FG
Status Light Status Pot Inner Plate Heating Element Heating Cover Bottom Lid Housing Outer Panel Cover Light Status Switch Plug Cord Assembly Temp Sensor lever Actuation Handle Spring Status Light Inner Pot Heating Plate 1 Heating Element 1 1 Bottom Cover Symmetric Lid Housing 1 1 Outer Panel 1 1 Status Light Cover 1 1 Switch 1 Plug Cord 1 1 Temp Sensor Assembly 1 1 Actuation lever 1 1 1 Handle 1 Spring 1 1
3.3.3 Step 3: Further Investigation and Analysis
Further investigation and analysis could be carried out depending on the purpose of the dissection and based on the findings during dissection. For example, a Design for Assembly [45] analysis could be performed to understand the product architecture and the assemblability of the product. If a group of products are dissected, then further platform identification analysis can be
43 conducted. Steva [11] provides two platform identification methodologies, which are the Bill-of
Materials Platform Identification Methodology (BOM-PIM) and the Function-Based Platform
Identification Methodology (FCN-PIM). BOM-PIM combines a DSM and a BOM while FCN-
PIM combines a Product-Function Matrix and a FCM to help identify platform elements in a family.
Other design issues such as the global, societal, environmental, and economic impact on the product design can be further considered and combined with the dissection analysis results.
The case study in Chapter 4 provides an example of discussing global and cultural impact on rice cooker design after dissection.
3.4 Comparison of Existing Work and Proposed Methodology
A three-phase methodology for product dissection based on existing methodologies is proposed in this chapter. The methodology is divided into three phases: (I) before-dissection, (II) during-dissection, and (III) after-dissection. Unlike the other methodologies that mostly focus on the systematic dissection process, this methodology puts the same amount of emphasis on function prediction and planning before dissection, the actual dissection procedures, and the analysis after dissection. The integrated methodology synthesizes the work of Otto and Wood
[1,2], Whitney [35], Ingle [31], Ulrich and Pearson [36], and Steva [11], and a comparison of the existing work and the proposed methodology is given in Table 3-6.
44
Table 3-6. Comparison of the exiting work and the proposed methodology
Phase Steps Sub-steps/Tools
]
5
]
3
1
Pearson
3
]
6
3
[
and
Proposed
Ingle [
Steva [11]
Whitney [
Methodology
Ulrich
Otto and Wood[1,2] Pre- List the design disassembly issues X Define purpose of dissection X Determine end use of data X Use/experience the product X Hypothesize the Black box model X X functions Fast diagram X Benchmark the market and design X of the product Gather list of Function structure and function X customer needs modeling Examine the distribution and X X Installation Plan product Determine data needed for collection X X disassembly Measurement selection X X
Tools selection X X Disassembly plan X X X Dissection Dissect the Identify physical connections before X X X Process product to the removing component lowest desirable Remove one component at a time, level photograph components before X X removal Take measurements on parts and X assemblies to complete the data sheet Document the Organize assemblies, subassemblies X X X X order of and components hierarchically disassembly Label removed components X X X X X X Record component attributes X List access direction X List orientation of product X Acknowledge/document expected X permanent deformation
45
Table 3-6. Comparison of the exiting work and the proposed methodology (Continued)
]
Phase Steps Sub-steps/Tools 6
3
]
5
]
3
1
3
Pearson[
and
Ingle [
Steva [11]
Whitney [
Otto and Wood[1,2]
Proposed Methodology
Ulrich List the tool usage X X X Take photos of disassembly X X X Execute Subtract and Operate Procedure X X X (SOP) Experiment with Identify main function of product components assemblies, sub-assemblies and X X (Non-SOP) components Identify degree of freedom X (DOF) Understand inclusion of X X parts/features Understand assemblability of X X X X X product Create BOM, BOM, exploded view, parameter exploded view, and list X X X X parameter list Experiment with X X X overall product Post- Function analysis, Energy flow diagrams, force flow Disassembly create refined analysis. X X Analysis function structure of actual product Create feasible sequence of X assembly and verify completion of data Create Morphological matrix morphological X matrix Create function sharing and X comparability Transform to House of Quality engineering specs & X Metrics (QFD) Create DSM and DSM, FCM FCM X X Execute platform BOM-PIM X identification FCN-PIM methodologies X
46 This methodology is intended primarily for educational purposes since it emphasizes the use of tools to understand product architecture and functionality, which students can combine with their background knowledge of product design, product architecture, and functionality to the hands-on experience of dissection. Two rice cookers are used as a case study to demonstrate the proposed methodology in the next chapter.
47 Chapter 4
Product Dissection Case Study---Rice Cooker
Based on the product dissection methodology proposed in Chapter 3, two different models of rice cookers are used as a case study. The models are the Panasonic SR-GO6FG and Aroma
ARC-150SB (see Figure 4-1). Panasonic SR-GO6FG is a basic rice cooker that only has one cooking mode, and the price is about $32 in the U.S. market. The features of SR-GO6FG include one-touch operation (i.e., with one touch of the “cooking” button, the rice cooker starts working and shuts off automatically) and a status light. The advantage of this model is that it is easy to use with simple one-touch operation, compact and portable, and easy to clean. However, this model does not have a keep-warm function.
The Aroma ARC-150SB is a mid-level cooker compared to the SR-GO6FG. It has several cooking options such as white rice, brown rice, and a steam function. It also has programmable steam and keep-warm modes, which the user can set to keep warm or steam for a specified amount of time. The price of the 150SB is about $37 in the U.S market.
Figure 4-1. Panasonic SR-GO6FG [52] and Aroma ARC-150SB [53]
48 4.1 Phase I: Pre-Dissection
In this phase, two major steps were taken. In Section 4.1.1, an investigation of rice cooker design and market segmentation are given. Preparation of a disassembly plan and a measurement choosing plan are given in Section 4.1.2.
4.1.1 Step 1: Investigation and Hypothesis
In this step, two rice cooker models are examined at first, and then rice cooker design and the market are benchmarked. The functions of the two rice cookers are predicted using black box models and FAST Diagrams.
Examination of the Two Rice Cookers
The Panasonic SR-GO6FG has a 120V, 60 HZ power supply and 310 W power consumption. The capacity of it ranges from 0.18L to 0.6 L, which allows it to cook up to 3 cups of raw rice. The accessories include a 180 ml measuring cup and a scoop. The Panasonic SR-
GO6FG has a one-touch setting. With a simple touch of the cook button, the cooking light turns on, and it starts cooking. After cooking is done, the cooking light turns off, and it will not automatically keep the rice warm.
The Aroma ARC-150SB is more sophisticated in terms of function and capacity. It is able to cook up to 10 cups of raw rice and has a digital control panel (see Figure 4-2). It offers functions for white rice, brown rice, steam, delay timer, and keep-warm. The programmable steam function enables the steam time to be set for 5 to 30 minutes and automatically shuts off once the time expires. It also has a 15-hour delay timer. Accessories include a measuring cup, steam tray, and a serving spatula. Other features include a locking lid and a water reservoir that
3 4 1
5
1 PARTS IDENTIFICATION 3 1 l a t i g i d a l l a t n a P . 8 1
r e d o p e d n ó t o B . 7
1 1. Lid Release r o p a v e d a r o d a c i d n i z u L 1 2
Button / r o p a v a r a p n ó t o B . 6 1
6
1 3
” e t n e i l a c 2. Handle
e s a g n é t n a m “ e d a r o d a c i d n i z u
L 3. Steam Vent
2 1
/ ” e t n e i l a c e s a g n é t n a m “ e d n ó t o B . 5
1 4 4. Lid
l a r g e t n i z o r r a e d a r o d a c i d n i z u
L 5. Condensation
/ l a r g e t n i z o r r a a r a p n ó t o B . 4
1 Collector o p m e i t l e d r o d a m a r g o r p 7 1
e d a r o d a c i d n I z u L / o p m e i t 5 6. Control Panel
1 1
l e d r o d a m a r g o r p l e d n ó t o B . 3
1 7. Inner Cooking Pot
8 1
o c n a l b z o r r a e d a r o d a c i d n i z u
L 8. Measuring Cup
/ o c n a l b z o r r a a r a p n ó t o B . 2
1 9. Serving Spatula
o t n e i m i c o c e d a r o d a c i d n i z u L . 1
1 10. Steam Tray
l o r t n o c e d o r e l b a T 6
8
7 9
10
49 0 1 channels away excess condensation. The manual and cooking guide for the rice cookers can be
found in Appendix9 A. 7 8
6 Control Panel
r o p a v e d a l o r a h C . 0
1 11. Cooking Indicator Light r i v r e s a r a p a l u t á p s E . 9
r i d e m a r a p a z a T . 8 12. White Rice Indicator Light
18 r a n i c o c e d a l l O . 7 White Rice Button
11 l o r t n o
c 13. Delay Timer Button/ 5
e d o r e l b a T .
6 17 Delay Timer Indicator Light
n ó i c a s n e d n o
c 14. Brown Rice Button/ e d r o d e g o c e R .
5 Brown Rice Indicator Light a p a T . 4
4 12
r o p a v 15. Keep-Warm Button/
e d r o d a l i t n e V . 3 Keep-Warm Indicator Light
3 a j i n a M .
2 16 16. Steam Button/
a p a t a l r i r b a a r a p
1 2 Steam Indicator Light
r o d a s l u p n ó t o B .
1 17. Power Button
13 S E T R A P S A L E D N O I C A C I F I T N E D I 15 18. Digital Display
14 3
Figure 4-2. Aroma ARC-150SB control panel [54]
Benchmarking of the Rice Cooker
The idea for a rice cooker came from a rice-cooking box used by the Japanese Imperial
Army in late 1930s [56]. The rice-cooking box was a wooden box with two electrodes attached to
apply current. The Mitsubishi Electric Corporation of Japan was the first company to produce the
commercial electric rice cooker back in 1945 [56]. The rice cooker was an aluminum pot with a
heating coil, but it could not be turned off automatically, often produced undercooked rice, and
required constant monitoring during the cooking process. The first practical rice cooker model
was invented by Yoshitada Minami [57], who was associated with Toshiba Electric Corporation.
Toshiba Corporation introduced the first commercially successful automated electric rice cookers
to the market in 1956. This model had huge success in the Japanese market; Toshiba was
50 producing 200,000 rice cookers per month afterwards. In the early 1960s, rice cookers could be found in half of Japanese households [57].
In the early age of rice cooker manufacturing, electric rice cookers were manufactured, marketed, and purchased mostly in Japan. With the rise of the mass production in China, most simple function models were manufactured in China. As the average household income rose in
Asia, many rice-consuming Asian countries became large manufacturers and consumers of electric rice cookers including Korea, Taiwan, and Malaysia. A recent survey showed that over
95% of Japanese households now have rice cookers [58]. In China, every 100 urban households reportedly own more than 100 rice cookers [59]. The rice cookers manufactured in China and
Korea focus more on simple feature models because of the market, where price competition is more important than various features. Meanwhile, the most high-end models are only available in the Japanese domestic market. With the trend of Asian cuisine spreading worldwide, rice cooker models were exported to western countries, and nowadays the U.S. is an emerging market for rice cookers [58].
There are reportedly a hundred fifty or sixty rice cooker manufacturers and at least hundreds of brands [58]. In the U.S., for the sake of the potential market and the high profit yet low technology requirements, lots of companies started competing in the rice cooker market. Rice cooker manufacturers can be categorized into three different types. The first type is “Mega-
Type”, such as Beauty Brand in China, the main products of which are entry-level rice cookers via mass production. Aroma Housewares Company is also an example of the first type. The second type is “High-End Type”, of which the typical manufacturers are Zojirushi, Panasonic,
Hitachi, Sanyo, Toshiba, and Philips, the new products of which are at the technological forefront. The third type is “Derivative Group”. Brands such as Haier, TCL, Gree, Glanz, etc. are traditional home appliance enterprises that have expanded their business into the rice cooker market with their own product lines [58].
51 The different types of rice cooker manufacturers provide different levels of product offerings. In terms of functions, features, and technology used, rice cooker models in the market can be categorized roughly into four levels. The first level is the “basic” model with affordable price and a single cooking function. Some of these entry-level cookers have an automatic keep- warm function, which will keep the rice warm when it is done. The second level is the “good” level, which has common features such as cool-touch housing and keep-warm mode. The “better” model is the next level, wherein most rice cookers have special cooking functions such as cooking different types of rice, delay-timer, and a programmable control panel. The highest-level
“best” models are at the technology forefront.
ii Table 4-1. Rice cooker market segmentation
U.S. Manufacturer Japanese Manufacturer China/Taiwan Manufacturer Best Aroma ARC-856， $65.88[60] Zojirushi NP-LS10 [61] Philips HD4761 Galanz B1100T-50PH7B 12-Cup Fuzzy Logic Cool Touch $1245* Pressure Heating Cooker $439 [63] ** [62] Approx. $250
Better Aroma ARC-150SB [64] Panasonic SR-DE102, Zojirushi NS-ZCC18 Midea FS406 Galanz B801T- $36.92 $84.99 $184.77 [66] $68** [67] 40F8G [68] 5-Cup Neuro Fuzzy $68** Fuzzy 10-cup Logic [65]
Good ARC-838TC [69] Maxi-Matic DRC- SANYO ECJ-N55W Sunpentown Sunpentown $ 34.6 1000B [70] $43.99 [71] SPT1083 SPT 1213 $29.99 $49.95 [72] $44.99 [73]
Basic Rival CKRVRCMO63 Aroma ARC-914B Panasonic SR- GO6FG [78] San Jiao Rice Cooker TATUNG [74] [75] $27.95 Price: $9 [79] TAC-6G (SF) $ 21.99 $23.88 $70 [80]
Aroma [76] Aroma ARC-733- [77] INGR ARC- $27.99 730G $ 29.99 * The price was exchanged from Japanese Yen to US dollars based on the 7/22/2011 currency. ** The price was exchanged from RMB to US dollars based on the 7/22/2011 currency exchange rules.
ii However, for different manufacturers in the U.S., Japan, and China, the rice cookers provided in each level vary in price, functions, and features. For example, the better models by the U.S. manufacturers usually offer options for white rice and brown rice while Japanese manufacturers offer a sushi rice option. A market segmentation grid is provided in Table 4-1 with example rice cookers in different levels from different manufacturers. Some of the example rice cookers are only available in the domestic market of the manufacturers; thus, the price is converted from the original currency to U.S. dollars. There are many variations on the prices of cookers based on exportation and importation issues. Moreover, the differences between different levels of rice cookers by U.S. manufacturers do not vary as much by Japanese manufacturers and by Chinese or Taiwanese manufactures. This may be due to the fact that the U.S. rice cooker market is still growing [49], and most of the product offerings are entry-level rice cookers. Thus, the prices are similar across the different segments by U.S. manufacturers.
Household rice cookers are able to cook 3-10 cups of uncooked rice, which is approximately 6-20 cups of cooked rice. Industrial-size rice cookers that are capable of cooking
100 cups of cooked rice are also available for commercial use. Other than capacity, rice cooker designs vary by style, functions and features, and technology used. The following paragraphs discuss different rice cooker designs and trends to understand the product and prepare for dissection.
The most popular rice cooker styles in the U.S. are pot-style and cool-touch rice cookers.
In a pot-style rice cooker, the inner pot has handles and is placed into the rice cooker body then covered with a glass lid. Cool-touch rice cookers usually have sealed locking lids, and the cooking pots are inside the body. An example of a pot-style rice cooker is the Aroma ARC-914B while a cool-touch model is the Aroma ARC-737-1G as shown in Figure 4-3.
54
Figure 4-3. Pot-style rice and cool-touch rice cookers [81,82]
The least expensive rice cooker models in the market are all one-touch operation cookers, and they are in the basic level in the market segmentation. The user pushes the “start” button of the cooker, and when the rice is done, the unit shuts off automatically. The one-touch cookers are constantly best-selling models in the market with a price around $30. Examples of this type of cooker are Rival CKRVRCMO63 and Aroma ARC-914B as shown in Figure 4-4.
Figure 4-4. One-touch operation rice cooker models [82,83]
The cook and keep-warm rice cookers reduce the heat by using a “warm” function when the rice is done. The temperature and the cooking duration of the “keep-warm” setting are different from the cook setting. This type of model is categorized as “good” model in the rice cooker market segmentation. It has a large market, and the price ranges from $30 to $70.
55 Examples of cook and keep-warm rice cooker are the Aroma ARC-838TC and Maxi-Matic DRC-
1000B shown in Figure 4-5.
Figure 4-5. Aroma ARC-838TC and Maxi-Matic DRC-1000B [84,85]
Controlled by electrical boards or even microcomputers, electronic or microcomputer type rice cookers offer more functions such as long-time keep-warm and delay timers. The price usually starts at $40 and goes as high as over $100. Some of the better-level rice cookers aimed at the U.S. market usually have brown rice/white rice options to meet the different cultural needs, while in the Asian market, rice cookers offer fewer rice variety options but more cooking options such as porridge cycle and sushi rice. Examples of this type of cooker are the Aroma ARC-150SB and Zojirushi NS-ZCC18 shown in Figure 4-6.
Figure 4-6. Aroma ARC-150SB and Zojirushi NS-ZCC18 [86, 87]
56 For the “best” rice cooker models in the market, advanced technologies are used such as fuzzy-logic and induction heating, and a combination with pressure cooking. Fuzzy-logic rice cookers have computer chips that control their ability to make proper adjustments to cooking time and temperature. The mathematical programming of fuzzy-logic rice cookers enables customized cooking options since the rice cooker is able to make precise adjustments to the amount of heat based on the amount of water and the amount of heat absorbed by the food [88]. . A fuzzy-logic rice cooker model is shown in Figure 4-7.
Figure 4-7. Zojirushi's NS-ZCC18 Neuro Fuzzy 10-cup [87]
Even with all these features, fuzzy-logic rice cookers are not the most advanced rice cookers available. Induction heating (IH) [89] is now the most advanced technology used in rice cookers. IH rice cookers are usually microcomputer controlled and can compensate for any initial errors such as adding too much or too little water and still deliver properly cooked rice [89].
Rather than heating the inner pot in a traditional manner, induction heating technology uses electromagnetic energy for heating. The heat is conducted deeply and evenly into individual rice grains, thus producing a fluffier rice textures [80]. Induction heating technology is usually
57 combined with pressure control technology, and one example of these models is the Zojirushi
NP-LS10 shown in Figure 4-8.
The high-end multi-functional rice cookers are able to steam food, cook different types of rice, slow cook soups and even make cakes and cookies. Some models even have a texture setting, which allows the selection of hard or soft and sticky or wet textures.
Figure 4-8. Zojirushi NP-LS10 [90]
The trend of rice cooker design is now toward multi-function, better inner pot material, and intelligent heating technology. The function of many rice cookers is no longer just cooking rice, but it extends into steaming and making soups and cakes. Pressure cooking is now a popular technology used in rice cooker design [58]. Through pressure cooking, more heat is preserved while cooking, and thus a lot of energy is saved. Also due to the high pressure, cooked rice tastes fluffier and stickier. The Philips HD4761 shown in Figure 4-9 is one of the best-selling pressure cooking models in the market [91].
58
Figure 4-9. Philips HD4761 [91]
The pursuit to improve rice cooker design to make them multi-functional, easy to operate, and intelligent never stop. The Zojirushi NP-LS is one of the best-level rice cookers (see Figure
4-10). It is only available in the Japanese market with a price around $1250, and it represents the best technology and the trend of rice cooker design. It has functions such as cooking rice and sushi rice, steaming, firing, making cakes, etc. Its other features include a LCD controller and a programmable melody to indicate when cooking is done. The Zojirushi NP-LS combines IH technology and pressure cooking, and thus it is very energy efficient.
Figure 4-10. Zojirushi NP-LS10 [90]
59 Function Prediction
Two models are used to predict the function of the two rice cookers. Black box models given general functions prediction on the cookers, and based on that, a FAST Diagram further predicts basic functions, secondary functions, and sub-functions in a hierarchical structure.
Before actual dissection of the two rice cooker models, the black box model was generated so better understand product functions. Two black box models (see Figure 4-11 and
Figure 4-12) are generated for the two rice cooker models.
Figure 4-11. Black box model for Panasonic SR-GO6FG
Figure 4-12. Black box model for Aroma ARC-150SB
Since Aroma ARC-150SB has a steam function, while Panasonic SR-GO6FG has only one-touch setting, the primary function of ARC-150SB is to cook or steam rice. The signal inputs
60 and outputs are different in the two models since ARC-150SB has a delay-timer function and
LED display, while the SR-GO6FG only has one indicator light to signal the cooking process.
The material and energy flows are similar in both models except that the Aroma ARC-150SB is capable of steaming food; thus, food is also in the material input besides rice, water, and human
(setup).
Two FAST diagrams are generated (see Figure 4-13 and Figure 4-14) before actual dissection of the two models to further predict the functions of the two rice cooker models. The critical path functions are the same for the two models since they share the same overall product function, i.e., cook rice. Unwanted functions are also the same since the two cookers would generate steam and heat during cooking. However, the sub-functions vary in the two models since the ARC-150SB has keep-warm and delay-timer functions, whereas the SR-GO6FG does not.
61
Figure 4-13. FAST Diagram for Panasonic SR-GO6FG
62
Figure 4-14. FAST Diagram for Aroma ARC-150SB
63 4.1.2 Step 2: Dissection Plan and Preparation
Before actually dissecting the two rice cookers, dissection plans and preparations were developed to determine the steps of dissection, information needed, and dissection tools to obtain.
Table 4-2 lists the rice cooker dissection plan.
Table 4-2. Rice cooker dissection plan
Product Disassembly Project Name Rice Cooker Dissection Engineer(s): Kang Kang Date: Oct. 2010
Known Desired Information: How rice cooker works, the components, the connections, how functions achieved
Disassembly Plan: Step Task Needed Tools Lid and cooking pan Material identification Cross-head screw Bottom and handle Flat-head screw, hammer Control Panel Physical connection Flat-head screw Button in the center of the Mechanism Cross-head and flat-head heating plate screw Heating plate Connections Cross-head screw Plug cord Connections
Measurements: Material of components, weight and dimensions of components
Comparison with Predictions: Functions, features, components, connections
64 Table 4-3 lists the worksheet for choosing measurement tools for the rice cookers. Data to be collected are determined, and accordingly, measurement tools and units of measurement are selected. After gathering the necessary tools for dissection and measurement, the actual dissection can be conducted.
Table 4-3. Rice cooker worksheet for choosing measurement tools
Related Functions Dimension, Weight, Cooking Time
Measurement: Length, Height, Width, Radius, Thickness, Weight Units: mm Range: 0-100 Accuracy 0.1
Measurement: Cooking Time Units: minute Range: 1-100 Accuracy: 1
Measurement: Weight Units: g Range: 0-3000 Accuracy 0.01
Current Devices: Range Accuracy Measurements Vernier caliper 140mm 0.05mm Length, height, width, thickness Measuring Tape 1520mm 1mm Length, height, width, thickness Watch 1 min Cooking time Electronic scale 180kg 0.1kg Weight Electronic scale 400g 0.1 Weight
65
4.2 Phase II: During-Dissection
After preparing the disassembly plan and measurement plan for the two rice cookers, the actual product teardown was performed. The rice cookers were dissected to the lowest level, and the process of disassembly was documented.
4.2.1 Step 1: Dissection of the Product to Lowest Level
Photographs were taken of the assemblies and sub-assemblies before and after removal.
Figure 4-15 shows the photographs taken before and after removing the switch of the Panasonic
SR-GO6FG during the dissection. The connections of components were also captured through photographs as shown in Figure 4-16. Figure 4-17 (a) and 4-17 (b) show the connection between the thermostat and actuation lever of the SR-GO6FG. Each component isremoved, examined, photographed, measured, labeled, and finally added to the Bill-of-Materials (BOM) for each rich cooker.
(a) Before removing the swatch (a) After removing the swatch
Figure 4-15. Removing switch from SR-GO6FG
66
(a) Aroma ARC-150SB (b) Panasonic SR-GO6FG
Figure 4-16. Physical connections of Aroma ARC-150SB and Panasonic SR-GO6FG
(a) Connect (b) Disconnect
Figure 4-17. Thermostat and actuation lever of model SR-GO6FG
4.2.2 Step 2: Documentation of the Process of Disassembly
The BOMs of the two rice cooker models organize components by subassembly and include data such as function, mass, finish, manufacturing process, and dimensions. Table 4-4 and
Table 4-5 list the BOM of major components of the two rice cookers by subassemblies. A more detailed BOM with all the components and pictures of each component are listed in Appendix B.
ii
Table 4-4. BOM for the Panasonic SR-GO6FG
Material List Panasonic SR-GO6FG Part # Part Name QTY Function Mass Material Manufacturing Dimensions (g) Process (mm) Rice Cooker A 1 Housing Assembly 1 Housing 1 Isolate the heat 399.5 Steel Forming Height 132 2 Handle 2 For hands to grab 6.4 Plastic Molding 3 Plug Cord 1 Connect to electricity 65.9 Composite Length 920 4 Outer Panel 1 Show cooking status 12.3 Plastic Molding Height 85 Width 70 5 Bottom Cover 1 Emit heat 37.5 Steel Stamping Radius 60
A 2 Status Light Assembly 6 Status Light Board 1 Light on/off to show cooking 6.7 Composite Wire Length status 140 7 Status Light Cover 1 Fix status light and wire to 4.0 Plastic Molding Height 49, housing Length 46
A 3 Temp Sensor Assembly 8 Thermal Magnet 2 Connect and initial cooking, 27.3 Magnet disconnect under certain degree and end cooking 9 Spring 1 Support and provide resistance 3.9 Steel Extrusion Height 40, force Radius 18
68
Table 4-4. BOM for the Panasonic SR-GO6FG (Continued)
Part Part Name QTY Function Mass Material Manufacturing Dimensions # (g) Process (mm) A 4 Actuation Assembly 10 Switch Base 1 Fix Switch 12.3 Steel Forming 11 Switch 1 Connect with lever and 8.0 Composite Composite Temp sensor, start and stop cooking 12 Actuation lever 1 Push to start cooking 13.1 Steel+Plastic Forming + Length 104 Molding
A 5 Lid Assembly 13 Lid with knob 1 Cover cooking pot 241.8 Plastic + Radius 85 Glass
A 6 Heating Assembly 14 Heating Element 2 Transfer electricity to heat N/A Iron Forming Radius 8 15 Heating Plate 1 Conduct heat 294.0 Iron with Machining Outer Radius Coating 58.5, Inner Radius 23.5
16 Cooking Pan 1 Cook Rice 141.8 Aluminum Forming Radius 150 with Coating Height 90
69
Table 4-5. BOM for the Aroma ARC-150SB
Material List Aroma ARC-150SB Part # Part Name QTY Function Mass (g) Material Manufacturing Dimensions Process (mm) Rice Cooker A 1 Case Assembly 1 Case 1 Indicates the functions and 517.6 Steel+ Forming+ Radius 132, options Plastic Molding Height 206 2 Outer Control Panel 1 Provide options and show N/A Plastic Molding Height 110, status Length 90 3 Condensation Collector 1 Collect condensed steam 13.8 Plastic Molding 12x61x85 4 Condensation Collector 1 Removable and clean 13.2 Plastic Molding 21x70x51 Cover
A 2 Lid Assembly 5 Lid with Handle 1 With Release button 414.1 Plastic Molding Radius 133 6 Steam Vent 1 Vent out excess steam 3.18 Plastic Molding Lower Radius 15 Upper Radius 20 7 Rubber Seal 1 Seal the lid with body N/A Rubber Radius 130
A 3 Central Control Assembly 8 Inner Control Panel 1 Receive chosen functions 40.4 Composite Composite 83x58 and connect with control board 9 Control Board 1 Control cooking time and 92.3 Composite Composite 101.5x61 temperature 10 Control Board Cover 1 Fix control boards to Case 54.6 Plastic Molding 120x62x64
70
Table 4-5. BOM for the Aroma ARC-150SB (Continued)
Part # Part Name QTY Function Mass (g) Material Manufacturing Dimensions Process (mm) A4 Temperature Sensor Assembly 11 Thermal Resistor 3 Increase the resistance 0.8 Length 4 when temperature goes up 12 Cover and Wire 1 Cover the thermal resistor 15.1 Plastic Molding Wire length 440 and contact the cooking pan
A5 Heating Assembly 13 Heating Element 2 Convert electricity to Heat N/A Iron Forming Radius 8 14 Heating Plate 1 Conduct heating 8.78 Iron with Machining Outer Radius coating 82.5, Inner Radius 25
A6 15 Cooking Pan 1 Cook Food 357.5 Aluminum Forming Radius 120, with Height 144 Coating
ii
4.3 Phase III: After-Dissection
After dissecting the rice cooker, analysis of the functionality of the two models was conducted to understand each component, the way it is connected to other components, and the function(s) it performs.
4.3.1 Step 1: Experiment with the Whole Product
After all the information is documented in BOMs, the two rice cookers were reassembled and tested. The operation of the two rice cookers was examined, and their functionality was ensured. This step ensures that the functions of the two rice cookers are properly identified and verifies that the documented connections are correct. After the experiment with the two reassembled rice cookers, further analysis was conducted.
4.3.2 Step 2: Analysis and Better Understanding
After dissection, the function structures of the two models were updated in terms of the three types of flows: energy, material, and information. The updated function structures are shown in Figure 4-18 and Figure 4-19.
72
Figure 4-18. Function structure for the Panasonic SR-GO6FG
73
Figure 4-19. Function structure for the Aroma ARC-150SB
Based on the two function structures, it is obvious that the two models vary a lot in functionality. Panasonic SR-GO6FG has only one setting while Aroma ARC-150SB has settings such as brown rice, white rice, steam, keep-warm, and programmable delay-timer. Thus, the information and energy flows are more complicated in the Aroma model than in the Panasonic
74 model. The information flows in the Aroma ARC-150SB contain the choice of functions input and status output; thus, the status of brown rice, white rice or steaming, cook or keep-warm, time left in delay-timer are shown in Aroma ARC-150SB while the Panasonic one only shows the status of “cook” and “off”. The material flows are similar in the two models since the material inputs are always rice (or food), water, and human (hand) to clean the mixture of rice and water.
Table 4-6 and Table 4-7 list the FCMs of the two rice cooker models. Only key components are listed. Full FCMs with all the components are included in Appendix B.
Table 4-6. FCM for the Panasonic SR-GO6FG
Cover
FCM of Panasonic SR- GO6FG
Status Light Status Pot Inner Plate Heating Element Heating Cover Bottom Lid Assembly Temp Sensor Housing Outer Panel Light Status Switch Plug Cord lever Actuation Handle Spring Connect to Electricity 1 Switch Power On/Off 1 1 1 Convert Electricity to Heat 1 Chanel Heat 1 1 Conduct Heat 1 Sense Heat 1 1 Indicate Cooking Status 1 1 1 Transmit to User 1 1 Cleanable Inner face 1 Non-Stick Surface 1 Cool-touch 1 1
75
Table 4-7. FCM for the Aroma ARC-150SB
FCM Aroma ARC-150SB
nsation Collector nsation
Outer Control Panel Outer Control Cooking Pot Plate Heating Element Heating Housing Inner Lid Button Lid Release Seal Lid Rubber Lid Handle Case Panel Control Inner Board Control Cover Board Control Assembly Sensor Temperature Resistor Thermal Vent Steam Conde Cover Collector Condensation Spring Connect to Electricity Switch Power On/Off 1 1 1 Initial Setting of Functions 1 1 Brown/White Rice 1 1 1 1 1 Programmable St 1 1 1 1 1 Keep Warm Option 1 1 1 1 1 Delay Timer Option 1 1 1 Convert Electricity to Heat 1 1 Chanel Heat 1 1 1 Sense Heat 1 1 1 Regulate Electricity 1 1 1 1 1 1 1 Automatically Keep Warm 1 1 1 1 Digital Display 1 1 1 Manual Input 1 1 1 Cool Touch 1 1 Condensation Collecting 1 1 1 Transmit to User 1 1 Cleanable Interface 1 Non-Stick Surface 1
76 Based on Table 4-6, the heating element and heating plate (the heating assembly) and inner pot performs most functions. In the Aroma ARC-150SB, the electric board assembly performs the most functions since it contains the settings of different options and a timer, and it controls the temperature for cooking or keep-warm functions. From both FCMs, assemblies and components such as the housing assembly, the temperature sensor assembly, the heating assembly
(including heating element and heating plate), the lid assembly, the control panel assembly, and the inner pot are the key assemblies and components, which perform sub-functions on the critical path. Thus further comparisons of the mechanisms and designs of these assemblies and components are conducted in Section 4.4.1 during Phase III of the methodology.
Two partial DSMs are shown in Table 4-8 and Table 4-9 for the two rice cookers. Only key components are listed. Full DSMs with all the components are included in Appendix B. Since the component-based DSMs are always symmetric along the diagonal (see Section 2.3.3), the other halves of the DSMs are not shown in the tables. The two rice cooker DSMs differ substantially since the components in two rice cookers are very different. The Aroma ARC-
150SB uses an electrical control board to control the heating and different cooking options while the Panasonic SR-GO6FG uses purely mechanical means to control heating and shut off. The two
DSMs differ in the number of components and average interactions. The DSM of the Panasonic
SR-GO6FG has 24 components, and the average number of interactions is 1.542. The DSM of the
Aroma ARC-150SB has 28 components, and the average number of interactions is 1.964. The average number of interactions is computed by dividing the number of cells with “1” by the total number of cells in the DSM.
77
Table 4-8. DSM for the Panasonic SR-GO6FG
DSM of Panasonic SR-GO6FG
Status Light Status Pot Inner Plate Heating Element Heating Cover Bottom Lid Housing Outer Panel Cover Light Status Switch Plug Cord Assembly Temp Sensor lever Actuation Handle Spring Status Light Inner Pot Heating Plate 1 Heating Element 1 1 Bottom Cover Symmetric Lid Housing 1 1 Outer Panel 1 1 Status Light Cover 1 1 Switch 1 Plug Cord 1 1 Temp Sensor Assembly 1 1 Actuation lever 1 1 1 Handle 1 Spring 1 1
78
Table 4-9. DSM for the Aroma ARC-150SB
Cover
DSM For Aroma ARC-150SB
Outer Control Panel Outer Control Cooking Pot Plate Heating Element Heating Housing Inner Lid Case Panel Control Inner Board Control Cover Board Control Assembly Sensor Temperature Resistor Thermal Vent Steam Collector Condensation Collector Condensation Spring Outer Control Panel Cooking Pot Heating Plate 1 Heating Element 1 Symmetric Inner Housing 1 1 Lid Case 1 1 Inner Control Panel 1 1 Control Board 1 1 1 Control Board Cover 1 1 1 Temperature Sensor Assembly 1 1 1 Thermal Resistor 1 1 1 Steam Vent 1 Condensation Collector 1 Condensation Collector Cover 1 1 Spring 1 1
79 4.3.3 Step 3: Further Investigations and Analysis
The two rice cooker models differ in their components (see BOM in Table 4-4 and Table
4-5) and functions (see black box model in Figure 4-11 and Figure 4-12 and FAST diagram in
Figure 4-13 and Figure 4-14, and function structure in Figure 4-18 and Figure 4-19), and thus result in the differences in the mapping between functions and components (see FCM in Table 4-
6 and Table 4-7) and connections between components (see DSM in Table 4-8 and Table 4-9). A comparison of each design is also conducted regarding the major assemblies and components, which serve important functions as seen in the FCMs. Table 4-10 provides pictures of three assemblies and components and also highlights major differences in the rice cooker designs.
ii Table 4-10. Comparison of key assemblies and components
Components The Control Assembly Temperature Sensor Assembly Heating Assembly Lid Aroma ARC
Panasonic SR
Difference Different mechanism: Aroma one uses Mechanism: Aroma one uses Size: Aroma one: radius= Design: Aroma one uses electronic-board control; Panasonic one thermal magnets; Panasonic 82.5mm rubber-sealed lid with uses pure mechanical control. uses thermal resistors Panasonic one: steam vent, Panasonic radius=58.5mm. one uses plain glass lid. Components Housing and Case Assembly Control Panel Inner Pot Aroma ARC
(1) (2) Panasonic SR
(5) (3) (4) Difference Different from design and materials. Aroma one has Design: Aroma one uses control board to offer Capacity and Material: case (1) and housing (2). Panasonic one uses a special the options, while Panasonic one only has a Aroma one is capable of shaped housing (3), (4) and a bottom cover (5). actuation level to operate cooking. cooking up to 10 cups while Panasonic one’s only 3.5 cups.
ii One of the interesting findings from dissection is the different design of the temperature sensor assembly. The Panasonic SR-GO6FG uses a magnetic thermostat mechanism to sense the heat level; it is a spring-loaded button in the center of the heating plate (see Figure 4-20 (a)). The button contains a magnetic thermostat (see Figure 4-20 (b)) and an outer spring. The thermostat senses the temperature and operates the off-on switch (see Figure 4-20 (c)). There are two springs in the temperature sensor assembly: one sits outside the thermostat, and the other is inside of the thermostat. The outer spring keeps the thermostat touching the cooking pot at all times while cooking. It provides support so that the thermostat can sense the temperature of the cooking pot and shut off. The inside spring works as a counter-force for the two thermal magnets; it is used to separate them when the magnet is weakened by the heat of the pot.
(a) Thermostat with spring (b) Thermostat magnets (c) Thermostat and lever connection
Figure 4-20. Temperature sensor assembly, Panasonic SR-GO6FG
The temperature assembly in the Aroma ARC-150SB works in a different way. It also uses a spring to keep the thermostat touching the cooking pot at all times while cooking, but instead of using two thermal magnets, it uses thermal resistors, which increase in resistance when the temperature of the inner pot rises (see Figures 4-21 (a), (b)). The temperature assembly is connected to the central electric board and thus sends a signal to shut off.
82
(a) Temperature sensor with spring (b) Thermal resistor
Figure 4-21. The temperature assembly in Aroma ARC-150SB
Based on the function analysis conducted after dissection (see Section 4.3.2), the two models differ in their functionality due to the different target market and customers. From benchmarking (see Section 4.1.1), the Aroma ARC-150SB is categorized as a “better” model and is produced by a U.S manufacturer while the Panasonic SR-GO6FG is a “basic” model in the market segmentation and is produced by a Japanese manufacturer. This different market segmentation may result in the difference in functionality. In terms of customer needs, the variations in rice cookers associated with cultural issues derive from the type of rice used in cuisines and the way of cooking rice. After the dissection and comparison of the two rice cookers, cultural issues stand out as an important aspect of rice cooker design, which affects the product functionality and architecture. Thus, further investigation on cultural issues of rice varieties, consumption, and cooking methods is conducted.
Further Investigation of Cultural Issues
About half of the world population survives on rice. As a cereal grain, it is the most important staple food for a large part of the world’s human population, especially in East and
South Asia, the Middle East, Latin America, and the West Indies [56].
83 Rice is the most important crop in Asia. For instance, 90% of the total agricultural area is used for rice production in Cambodia. Between 1961 and 2002, per capita consumption of rice increased by 40% worldwide [56]. Asia has long been the major rice consumption area. The
Green Revolution in Asia, which started in 1960s and introduced high-yielding rice varieties, brought a rapid rise in both rice yields and overall production [56].
U.S. rice consumption has risen sharply over the past 25 years [92]. It is reported that almost one in five adult Americans now eats at least half a serving of white or brown rice per day
[92]. The consumption of rice in the U.S. in 2003-2004 was 3.9 million tons according to U.S.
Department of Agriculture [93]. The consumption of rice by country from 2003 to 2004 is summarized in Table 4-11. The rise of rice consumption increased the market of rice cookers from the traditionally Asian area to a global market in the past 20 years.
Table 4-11. Consumption of rice by country 2003/2004 [94]
Country Million metric ton China 135 India 85.25 Indonesia 36.95 Bangladesh 26.4 Brazil 24 Vietnam 18 Thailand 10 Myanmar 10 Philippines 9.7 Japan 8.7 Mexico 7.3 Pakistan 6.0 South Korea 5.0 Egypt 3.9 United States 3.9
Rice is the seed of the monocot plant Oryza sativa. Worldwide there are more than
120,000 different varieties of rice [93]. These varieties can be divided into three types [93]: (1)
84 long grain, (2) medium grain, and (3) short grain (see Table 4-12). These three types differ in their cooking characteristics, texture, and some subtle flavor variation. Thus, these three types of rice fit different recipes.
Table 4-12. Rice varieties
Short Grain Rice Medium Grain Rice Long Grain Rice
[93] [93] [93] Cooked grains are more moist, Cooked grains are moist, Cooked grains are separate, tender and tend to cling tender and tend to cling firm and fluffy together together
To serve different consumer preference in different cultures, rice comes in different forms in terms of various degrees of processing: rough (paddy) rice, brown rice, regular milled rice (white rice), and parboiled rice. These rice forms are summarized in Table 4-13.
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Table 4-13. Rice types
Rough Rice Brown Rice White rice Parboiled rice
[93] [95] [96] [97] Rice kernels are still in The outer hull of the White rice has been The parboiled rice is an inedible, protective rice is removed, but completely milled soaked, steamed and hull the bran layer still and polished, dried before milling. retains. It has a removing the bran This steam-pressure chewy texture and a layer. creates a firmer and nutlike flavor. more separate texture
For different cultures, special varieties of rice are also cultivated. The two most common types of rice are Basmati rice and Jasmine Rice [93]. Basmati is a variety of long grain rice grown in India and Pakistan, and it has the longest grain of all rice types and a translucent appearance. It also has a distinctive spicy aroma and nutty flavor. When cooked, it is dry, separate, and fluffy, which matches spicy dishes perfectly. Jasmine rice, which is also known as Thai Fragrant Rice, is a long-grain variety of rice that has a nutty aroma. The cooked grains are soft, moist, and cling together, though it is less sticky than other white rice. To cook these two varieties, the desired cooking methods, time, and temperature are very different. For example, Jasmine Rice is best for boiling or steaming while Basmati is best for frying after boiling.
Different cultures have rice variety preferences, which dictate different cooking methods.
In Eastern and Southern Asia, white rice is the main rice variety in the daily diet; other rice varieties include purple rice and beany rice [98]. The traditional ways of cooking rice are boiling
86 and steaming using a boiling pan or steamer [56]. Eastern and Southern Asia countries have special preferred rice cuisines such as slow cooking rice (often called porridge or congee) and sushi in China, Korea, and Japan [99]. Rice is a common side dish in the Middle East; main dishes are served over rice, and normally the rice is fried first [100]. In India, they prefer rice consistency to be non-sticky and separate, and the preferred rice variety is Basmati rice. Yellow rice and Saffron rice are also cooked in Indian cuisines. There are several ways of cooking rice in
India, such as adding extra oil or ghee, or draining the rice and pouring room temperature water on top of the rice to drain off any remaining starch when the grains are cooked through. Also, spices can be added before cooking the rice or after steaming the rice [101]. Rice and beans are the core of Brazilian cuisine and also play a large part in the cuisines of many other parts of Latin
America, e.g., Cuba, Venezuela, Mexico, etc. [102]. The rice varieties used are brown rice and white rice.
4.4 Conclusions
As mentioned in Section 4.1.1, rice cooker models sold in the Japanese market are more high-technology oriented yet with less focus on the options for cooking different types of rice; these models are designed only for cooking Japanese white Jasmine rice. As mentioned in Section
4.1.1, most better-level rice cookers have options for cooking brown rice and white rice to accommodate different cultural cooking needs. A rice cooker model, which is designed for a certain culture, such as with a porridge or sushi rice function, can be easily found in the U.S. market.
This case study demonstrated the proposed methodology and identified several cultural issues in rice cooker design. The results serve as a basis for the rice cooker dissection activity created in the next chapter to expose students to these cultural aspects.
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Chapter 5
Exposing Students to the Cultural Aspects of Rice Cooker Design through Product Dissection
The dissection of two rice cookers in Chapter 4 indicates that there are a lot of global and cultural issues involved in rice cooker design. Thus a new product dissection activity was created to expose students to these cultural aspects. The activities, assignment, metrics for evaluation, and results of this experiment are discussed in this chapter after outlining the objectives for the experiment.
5.1 Experimental Objectives
As mentioned in Chapter 2, most engineering design courses emphasize the technology, function, and architecture of a product through dissection activities, and thus fail to address the global, economic, environmental, and societal impact of design. With globalization and environmental concerns becoming important criteria in engineering solutions, the need for providing students with an understanding of the global, economic, environmental, and societal issues in engineering design education is critical. An educational framework has been formalized to classify product dissection activities based on the level of the student involvement [19]. The framework and descriptions of each level are given in Figure 5-1.
Rice cookers were added to the appliance dissection section of the Spring 2011 offering of ME240: Product Dissection course at Penn State (see Section 5.2). The objective of adding
88 rice cookers to dissection activities is to address design concerns beyond the technology, and expose students to cultural issues as outlined in the first phase of the framework in Figure 5-1.
Descriptions of Quadrants in Framework: Why? st nd III. IV.I. Expose – Best suited for 1 and 2 year courses to familiarize students with products and artifacts in a structured way, to teach students engineering vocabulary and terminology, and to overcome any anxiety with engineering; INQUIRE EXPLOREmust be highly structured to ensure proper progress through the activities. II. Inspire – Useful in 1st and 2nd year courses to introduce design, graphics, or
Rev Engr reinforce fundamentals from engineering courses such as statics and Knowledge Guidance mechanics of materials; usually less structured to promote self-discovery. Max Min rd th
Engr Engr Dissection III. Inquire – Primarily used in 3 and 4 year courses to provide hands-on activities to reinforce engineering principles and theory; usually highly structured to ensure that the material is covered properly. IV. Explore – Appropriate for 3rd and 4th year design courses to support idea
EXPOSE Required INSPIRE generation, redesign, and benchmarking; application of ‘core’ engineering I. II. knowledge; or an integral part of a design process; usually requires the least How? amount of supervision – intended to foster self-discovery. Figure 5-1. Framework for classifying product dissection-based activities [103]
The case study in Chapter 4 serves as the preparation for the new in-class dissection activities. The cultural aspect of rice cooker designs were investigated, and key components were identified, including the mechanisms to be studied (e.g., thermostat). Based on the case study, a lecture on rice cooker design and cultural differences was created to explain rice types and dietary differences, and a new rice cooker dissection assignment was generated (see Section 5.3) based on the analysis and findings of the case study.
An experiment was conducted to collect and analyze the result of the rice cooker dissection activities. Since the rice cooker dissection was newly added into the in-class dissection activities, the objectives of the experiment are to collect responses from the students dissecting the rice cookers, analyze and summarize the results, and make suggestions for improving the assignment and course arrangement. The results of the experiment serve as baseline for future studies. Based on the comparison of the responses across several course offerings, further evaluations of the effectiveness of incorporating rice cookers in product dissection to expose students to the cultural impacts of rice cooker design can then be conducted.
89 5.2 Product Dissection at Penn State
Each spring, ME 240: Product Dissection is taught at the Pennsylvania State University.
It is a 3-credit course that is part of the Product Realization Minor [104]. Each year, 18-20 sophomore or senior students majoring mainly in mechanical or industrial engineering take the course. In the first 5 weeks of the course, bicycles are dissected. In Weeks 6-10, a variety of consumer goods are dissected, including a hand drill, residential telephone, and single-use camera. In the last 5 weeks of the course, students dissect, analyze, and reassemble a Briggs &
Stratton 4-stroke internal combustion lawnmower engine [105]. ME240 is taught concurrently with three first-year seminars: ME 105S: Bicycle Dissection, ME106S: Appliance Dissection, and
ME107S: Engine Dissection. Each first-year seminar performs one section of the ME240 dissection activities. Each first-year seminar has 12-18 first-year students who have not yet declared a major.
The course combines dissection activities and benchmarking methods to develop a basic aptitude for engineering design. It examines the way in which products and machines work, with emphasis on the physical operation, materials used, the methods of construction, and customer considerations that determine the design’s success in the marketplace. The primary objectives of the course are to develop a basic understanding of manufacturing and product design through hands-on laboratory experiences. Other than the traditional ways of delivering lectures in class, students work in pairs during dissection and thus their communication skills are emphasized during the whole class. Lectures and discussion topics include design process, material selection, introduction to manufacturing processes, basic mechanical and electrical components and measurements. These lectures are delivered prior to each dissection activity, serving as complementary instruction rather than main content of the course. Lecture materials and details
90 on the specific dissection activities can be found on the course website: http://www.mne.psu.edu/simpson/courses/me240/.
5.3 Rice Cooker Dissection Activity
Rice cookers were added to the appliance dissection section of the course in Spring 2011, and thirty students (freshmen through senior level) participated in this rice cooker dissection. Out of 30 students registered in the product dissection class, 24 responses were collected based on those that provided consent to their results being analyzed. Two to three students were partnered for the rice cooker dissection activity. Each group dissected a rice cooker model, reassembled and tested it, and then answered 11 questions over the period of two two-hour class sections. The assignment for the rice cooker dissection is in Table 5-1.
The rice cooker models provided for dissection are mostly entry-level small-capacity cookers, and students chose the model they were interested in dissecting. The detailed rice cooker models that were dissected are listed in Table 5-2. Model selection is based on the market segmentation grid and the investigation in Chapter 4. The basic models such as the Rival
CKRVRCMO03, Aroma ARC-733-INGR, Aroma ARC-914B, and Aroma ARC-730G (see market segmentation, Table 4-1) share the same thermostat mechanism (see Section 4.3.3) with the Panasonic SR-GO6FG. The “good” model, namely, the Sanyo ECJ-N55W from Japan, has a porridge/soup function, which satisfies a different dietary need for Eastern Asian countries (see
Section 4.3.3). This model also has the same thermostat mechanism as the Panasonic model. The
Aroma ARC150SB dissected in the case study was also provided to students, but it was not selected by anyone for dissection. Thus Questions 6-8 in the assignment (see Table 5-1) have correct answers based on the previous case study findings and investigations.
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Table 5-1. Rice cooker assignment
Penn State University Department of Mechanical & Nuclear Engineering
ME240 PRODUCT DISSECTION: APPLIANCES ME106S
Rice Cooker Dissection
Purpose: Compare and contrast the features and functionality of rice cookers.
Procedure (Record all answers in your journal):
1. Identify the make and model of your rice cooker along with its features and capabilities.
2. Note the power listed for your rice cooker. Is the power related to the number of cups of rice that can be cooked (look at other rice cookers)? Do you think a low power rice cooker saves more electricity than a high power rice cooker? Why or why not? (Note: High power rice cookers usually take 20 mins to cook rice while smaller ones take about 40 mins.)
3. Start disassembling your rice cooker with the lid. Sketch the lid, noting any special features it has (e.g., surface, vents, holes) and discuss why it is designed this way. If your rice cooker just has a plain lid, look at other lids to see what special features they have.
4. Separate the housing and the inner pot. How are these manufactured? What material(s) do you think they are made from and why? Also, does your rice cooker have a separate cooking pot? Why or why not?
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Table 5-1. Rice cooker assignment (Continued)
5. Take apart the heating element on the bottom and measure its diameter. Is it the same size as the heating elements in other rice cookers? Why or why not? What materials are present? How do you think it is manufactured? Is it a complete circle? Why or why not?
6. Sketch the mechanism of the temperature sensor of your rice cooker, and describe how the rice cooker senses the temperature and turn into keeping warm mode.
7. What is the purpose of the spring on the underside of the heating element? Could it be replaced by another type of mechanism? If so, what?
8. Use the following table to describe (with sketches and words) how the mechanisms inside your rice cooker work in response to:
Pushing start Keeping rice warm Indicating light is on button Heating Element
Temperature Sensor
9. Before reassembling your rice cooker, look at other models in the classroom and identify 2-3 different functions that other rice cookers perform. How are these functions achieved? Describe and sketch the mechanisms associated with these functions.
10. List some suggestions to improve the design of your rice cooker (e.g., materials used in housing, lid or inner pot; heating mechanism, temperature sensing; more functions).
11. Finally, how does the rice cooker accommodate the different cultural needs discussed in class or is it designed for a specific type of rice?
93 Table 5-2. Rice cooker models dissected in class
# of Model Photo Features/ Capacity Student Dissecting 3-Cups capacity Rival One touch operation CKRVRCMO63 Automatic keep-warm 3 Glass lid
3-cups capacity Panasonic One-touch operation SR-GO6FG Glass lid 2 Automatic keep-warm
Pot style Aroma 3-cups capacity ARC-733-INGR Glass lid 6 One-touch operation Automatic keep-warm
5-1/2-cup porridge/soup cooker and steamer Sanyo Single-switch operation ECJ-N55W 3 Keep-warm function
Sealed lid; steam vent and dew collector 4-cups capacity Aroma ARC-914B Cool-touch exterior 5 Keep-Warm function One-touch operation
4-cups capacity Aroma One-touch operation ARC-730G Automatic keep-warm 2 function Glass lid
Before students dissected their rice cookers, a lecture on different types of rice, dietary needs in different cultures, different rice cooking methods in different countries, and basic rice cooker designs was delivered by Dr. Timothy W. Simpson for about 30 minutes. The lecture was prepared based on the findings of the case study in Chapter 4. No discussion of the mechanisms or the components in the rice cookers were provided; instead, the intent of the lecture was to
94 provide an overview of rice cooker design and start to expose students to the cultural impact on design.
5.4 Metrics for Evaluation
Out of eleven questions asked in the assignment, Questions 6-8 and 9-11 relate to the cultural impact of rice cooker design. The other questions asked general questions such as how components are manufactured and what materials are used (Questions 4 and 5), the inspection of features (Question 1 and 3) while Questions 6-8 asked more specific questions about the mechanisms of certain components and the relationships between components and functions in the rice cooker. Questions 9-11 are more open-ended questions asking students’ for design improvements and whether the model dissected met certain cultural needs. Thus, Questions 6-11 are about rice cooker design and cultural issues and were selected for the evaluation of this experiment.
Questions 6-8 have correct answers based on previous rice cooker dissection activities and research on the rice cooker models dissected in class. Questions 9-11 are open-ended questions requiring feedback on functions identified, suggestions, and cultural issues. Thus, the correctness of the answers were calculated and compared for Questions 6-8 and summaries of students’ answers were collected for Questions 9-11.
5.5 Experimented Results
The answers to the correct-answer questions (Questions 6-8) are analyzed and compared in Section 5.4.1. Responses to the open-end questions (Questions 9-11) are summarized in
Section 5.4.2.
95 5.5.1 Summary of Correct-answer Questions
Summaries of Questions 6-8 are given in this section. The number of correct responses of each question is calculated and a short comparison is given at the end.
Understanding of the Mechanism of the Temperature Sensor Assembly (Question 6)
All the rice cooker models dissected in class have the same mechanism for the temperature sensor assembly as the Panasonic SR-GO6FG, i.e., the magnetic thermostat mechanism (see Section 4.3.3). Question 6 asked students how the temperature sensor works in their rice cookers after dissection.. The students’ responses to this question are evaluated based on the ability to identify the correct working of the magnetic thermostat and the switch. Out of total
24 students, 14 students described the mechanism correctly while 7 failed to explain in detail how the thermostat senses the temperature and operates the off switch. Meanwhile, 16 students mentioned in their answers the use of the thermal magnet, and among those, 10 students successfully identified that the thermal magnet and spring work together in the thermostat. The correct answers were collected and are summarized in Figure 5-2. Examples of correct sketches are shown in Figure 5-3 and Figure 5-4, and incorrect sketches are shown in Figure 5-6 and
Figure 5-7. Two students did identify the use of the thermal magnet in the thermostat but failed to address how those two magnets work together to sense the temperature and operate the switch.
Among all the responses, 4 out of 8 students who dissected rice cooker models with a “keep- warm” function correctly explained how the “keep-warm” function is realized by the double metal sheet mechanism in the rice cooker model, and sketched the mechanism as well (see Figure
5-5).
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Counts of Correct Answers to Thermostat Mechanism
# of Student (Out of 24)
19
12
5
Magnet Magnet+Spring Keep Warm
Figure 5-2. Summary of correct responses
The example sketch shown in Figure 5-2 is correct because this student was able to identify the working of the top magnet, bottom magnet, outer spring, and inner spring. In Figure
5-3, the sketch is also correct because the student was able to identify the connection of the spring, the heating element, the thermostat, and the switch. In Figure 5-6 and Figure 5-7, the sketches incorrectly identified the board that connects wires to the temperature sensor assembly.
Figure 5-3. Example sketch of thermosat mechanism
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Figure 5-4. Example sketch of thermostat mechanism
Figure 5-5. Example sketch of “keep-warm” mechanism
98
Figure 5-6. Incorrect example sketch of thermostat mechanism
Figure 5-7. Incorrect example sketch of thermostat mechanism
Understanding of the Rationale behind the Design (Question 7)
Question 7 asked students about the use of certain components in the design and have them rationalize the design, that is, why a certain component is used in the design and if it can be replaced. This question had the fewest correct responses among all 11 questions asked in the assignment. Only 9 students (43%) were able to answer it correctly. Typical incorrect answers include the spring working as a safety mechanism, which will shut off automatically when overheated. However, 9 students were able to identify the function of the spring correctly and suggested other mechanisms to serve the same purpose. One of the correct sketches is shown in
99 Figure 5-8; it identified the use of the outer and the inner spring. There is no comparable incorrect sketch because students failed to identify the function of the spring did not provide any sketches.
Figure 5-8. Example sketch of the function of the spring
Understanding the Relationship between Function and Component (Question 8)
Question 8 was in a table format (see Table 5-3) and asked students to think about the relationships between three basic functions (i.e., cooking, keep-warm, and indicating cooking status) and two key components (heating element and thermostat) of the rice cookers. By completing the table, students described how each function is achieved through the use of certain components.
100 Table 5-3. Table for answering Question 8
Push the start Automatically keep Indicating light button warm turns on Heating Element Temp Sensor
The number of correct answers to this question is summarized with respect to each function in Figure 5-9. This question received a relatively higher number of correct answers; only three students had problems correctly connecting the heating element and thermostat to the function of “start cooking”. An example response is shown in Figure 5-10, and an example sketch of the connections of components is shown in Figure 5-11.
Counts of Answers to Function and Component # of Student (Out of 24)
24 24
21
Start Cooking Keep Warm Cooking Status
Figure 5-9. Counts of answers to functions and component
101
Figure 5-10. Example response for function to component
102
Figure 5-11. Example sketch of connections
Comparison
A comparison of the results of Questions 6-8 is shown in Figure 5-12. It seems that it is not difficult for students to identify the relationship between one component and a certain function, such as describing how the thermostat works during cooking. Thus Question 8 received the highest number of correct responses (87.5%) among all. Question 7 received the lowest percentage of correct responses, which is only about 46%. This might be due to the fact that the most difficult part of reverse engineering is to fully understand the use of certain components in order to remanufacture them. Question 6 received a percentage of 67% correct, which also shows that it is difficult for students to understand exactly how certain components work. Possible improvements should be considered on how to help students better understand the mechanism of the thermostat and the use of spring. Some suggestions are given in Section 5.5.
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Correctness Comparison
Percentage of Correctness
87.5% 67% 46%
Thermostat Spring Components to Mechanism Function
Figure 5-12. Comparison of Questions 6-8
5.4.2 Summary of Open-ended Questions
Summaries of Questions 9-11 are given in this section. Students’ responses are collected and summarized in tables for each question. The complete list of student responses to Question 9-
11 can be found in Appendix C.
Functions/Features of other Rice Cookers (Question 9)
Question 9 encouraged students to explore other rice cooker models in the class and asked students to identify different functions or features. Most rice cooker models dissected in the class are basic one-touch models expect for one: Sanyo model (Sanyo ECJ-N55W). This model has a soup/porridge function. Eleven out of eighteen students (the three students working on the
Sanyo model were excluded) were able to identify this special function, which is a relatively high percentage (61%). Other than the basic models dissected in class, there are several other Aroma
104 Rice Cooker models such as Aroma 150SB that were not dissected (see Chapter 4). Some students were able to identify the features of those models such as delay timer, LED light indicator, etc. A summary of the answers is given in Table 5-4.
Table 5-4. Summary of students’ answers to Question 9
Functions/ Features Count (out of 24) Soup/ Porridge 11 Steam tray 10 Steam vent of the Lid; Button latches of the lid; locking lid 6 More options such as brown rice, white rice, steam function 5 Delay timer 4 Microcomputer temperature control /Electronic temp sensor 4 LED light indicator 2 Different settings of temperature and cooking time depending on the type of 2 rice being cooked Pressure release valves/pressure cooking 2 “Cool touch” housing 1 Different capacity (Cups of rice can be cooked) 1
Suggestions for Improvement by Students (Question 10)
Question 10 asked students to list suggestions for further improvement for the rice cooker they dissected. General suggestions focused more on the product functionality: nine out of twenty-four (37.5%) students suggested that more options such as cooking both brown rice and white rice should be added, and 6 students suggested adding options such as delay timer and LED indicator, which they identified from other rice cookers in Question 9 to facilitate the cooking process. Other answers include material selection, component redesign, manufacturing and global issues (e.g., suggestions on adding multiple languages to the control panel and manual and an universal power plug). The detailed summary of the students’ suggestions is listed in Table 5-5.
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Table 5-5. Students’ suggestions on rice cooker design
Category Suggestions Count (out of 24) Function More options such as cooking different rice types 9 Adding delay timer 3 Adding LED indicator 3 Adding steam tray 1 Options for different cups of rice to be cooked 1 Adding a more specific temperature sensor to show temperature on the outside 1 Aesthetics More compact 3 More appealing in appearance other than pure plastic 3 Material Better material of housing to achieve "cool-touch” 4 Better non-stick coating material of the inner pot 1 Changing the material of the lid to plastic or materials retains heat better than 1 glass Design Changing the simple lid into a sealing or vacuum design 3 Adding a steam collector 1 Changing locking lid to simple glass lid, which is easy to clean 1 A heavier bottom to prevent getting knocked over easily 1 Global More language other than English in the manual and control panel 2 Universal power plug 2 Sizes and Double the space of steaming 1 Capability A larger inner pot to cook more rice 1 Higher power to cook faster 1 Cooking Adapting Indirect cooking methods such as steam cooking to prevent burn 1 Principle Adapting Pressure cooking so that the cooker can use as pressure cooker as well 1 Assembly Better arrangement of the wire under the inner pot to ease the assembly 1
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Opinions on Whether the Rice Cookers Dissected Meet any Cultural Need (Question 11)
Question 11 asked students’ opinion on the cultural impact of rice cooker design.
Students gave various responses that can be categorized into five groups as summarized in Table
5-6. Over half of the students (11 out of 21) thought the basic rice cooker models they dissected could not meet different cultural needs because of the lack of multiple functions while only a few students (6 out of 21) thought the basic models have simple settings and are able to cook most rice. Compared to these two opinions, two students thought differently: the low-end models fit all needs while high-end models are designed to fit a specific culture. All the students dissecting the
Sanyo ECJ-N55W model thought that this specific model does accommodate specific cultural needs because of the special porridge/soup function.
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Table 5-6. Summary of Question 11
Opinion Count (out Model Dissected of 24) Lack of cultural diversity, could not meet 11 Rival CKRVRCMO63 different cultural needs Aroma ARC-733-1NGR Aroma ARC-914B Aroma ARC-730G Simple and general, able to cook most rice, 6 Aroma ARC-733-INGR fits all needs Panasonic SR-GO6FG Rival CKRVRCMO63 Aroma ARC-914B Porridge function does accommodate 3 Sanyo ECJ-N55W (has a different cultural needs; it’s more culturally porridge/soup function) specific. The low-end models fit all needs and all 2 Aroma ARC-730G culture; high-end models are more designed Aroma ARC-914B for one specific culture. Fits American fast paced lifestyle and 2 Aroma ARC-733-INGR culture only with its basic rice cooking option
5.5 Conclusions and Suggestions for Rice Cooker Dissection Activities
Rice cooker dissection generated a considerable amount of feedback on product functionality, suggestions for product design improvement, and the model’s ability to meet different cultural needs. The result of the experiment serves as a baseline for next year’s dissection activity. Conclusions from the experiment are given in Section 5.5.1. Suggestions based on the experimental results are given in Section 5.5.2.
108 5.5.1 Conclusions
Based on the results collected from the students’ answers to rice cooker dissection assignment, nine out of twenty-four (37.5%) students suggested adding more options such as cooking different types of rice to meet different cultural needs. In the feedback to the question asking about how the dissected rice cooker accommodates the different cultural needs, students gave various opinions among which the most popular answer was that the basic models they dissected lacked cultural diversity and could not meet different cultural needs. Moreover, eleven out of twenty-four (45.8%) students are able to identify the porridge function of one model
(Sanyo ECJ-N55W) and mentioned that it is designed for specific cultures.
As rice cookers were newly added to the consumer goods dissection section in the Spring
2011 course, the results of the assignment answers provide a baseline for future comparison and improvement.
5.5.2 Suggestions
According to the comparison in Section 5.4.1, Question 7 received the fewest correct responses (46%), and a lot of incorrect responses showed that students have difficulty understanding the functionality of certain components. More focus could be put on the discussion of cultural issues on product design since rice cooker models vary so much in the markets due to different cultures (see Section 4.3.3). Some improvements on the assignment and the rice cooker models selection could be made for future course offerings.
SOP (Subtract and Operate Procedure) could be used in class. For example, Question 7 can be rearranged as:
1) Operated the rice cooker as a whole
109 2) Take out the spring and operate the rice cooker again
3) What do you think is the difference that the spring makes?
4) Can you think of other mechanisms or devices that serve the same function as the
spring?
For a better understanding of cultural differences that impact rice cooker design, more models in different markets, e.g., rice cooker models sold in Japan or China, should be available for dissection. Thus students are able to better compare different functions and develop the idea of the difference in design due to different markets or cultural needs.
By adding more tools to more focused assignment and a wider range of rice cooker models, the goal of exposing students to the cultural issues on product design can be better achieved. A summary of the thesis and addiction future work is discussed in the next chapter.
110 Chapter 6
Summary and Future Work
6.1 Summary
This work describes a product dissection methodology and a case study involving two rice cookers to demonstrate the proposed methodology. The case study focuses on the functionality and product architecture of rice cookers and based on comparisons of the two rice cookers, the cultural impact on rice cooker design are identified. The methodology and the case study results serve as the basis for incorporating rice cookers in dissection activities in engineering education. The cultural issues uncovered in the case study define the focus of the rice cooker dissection activity to expose students to the cultural issues of rice cooker design.
An experiment was conducted with the rice cooker dissection assignment, and the responses were collected and analyzed including sketches of mechanisms and components, suggestions for improving the design, and feedback on cultural needs. Meanwhile, students’ difficulties in identifying the mechanisms in assemblies and the function of some components were discovered, and future improvements for the dissection assignment were suggested. The results of the experiment will provide a baseline for next year’s dissection activity and evaluation, and more importantly, for further evaluation on the effect of exposing students to cultural issues in product design.
111 6.2 Future Work
Future work on improving the proposed dissection methodology, the rice cooker dissection activity, and courses involving product dissection activities are discussed in this section.
6.2.1 Product Dissection Methodology
The proposed methodology in Chapter 3 can be updated to a methodology for dissecting a group of products and after-dissection analysis of the product family and product platform. The
Bill-of-Materials Platform Identification Methodology (BOM-PIM) and The Function-Based
Platform Identification Methodology (FCN-PIM) [11] can be integrated as well. BOM-PIM combines tools such as the DSM with product dissection information organized into a BOM while FCN-PIM utilizes Product-Function Matrix and Function Component Matrix (FCN). One continuing area of study is to improve these product platform identification tools and thus provide necessary information to reverse engineer a product platform.
Another continuing area of study is to integrate more benchmarking tools such as detailed customer needs assessment procedures and Quality Function Deployment (QFD). QFD is a methodology for defining the customer’s desire and transforming them into quantified engineering specifications [1, 2]. Thus, including this into the methodology could better support product redesign or the students’ hands-on experiences with product dissection and benchmarking.
112 6.2.2 Rice Cooker Dissection Activity
With globalization becoming an important trend in both industry and academia, it is very important for students to understand the impact of cultural differences. Cultural impact on product design should be addressed and discussed in engineering design classes, and ABET (the
Accreditation Board for Engineering and Technology) requires it [106]. Based on the results of the experiment introduced in Chapter 5, a lot of improvements can be made, such as a more focused assignment and a wider range of products to dissect. Future evaluations of the effect of rice cooker dissection activities on exposing students to cultural issues in product design should be conducted, comparing results to the Spring 2011 product dissection activity. More importantly, rice cooker dissection could be incorporated into higher levels of the product dissection framework to inspire, inquire, and explore different aspects of engineering design [19].
6.2.3 Engineering Design Education Incorporating Product Dissection
Product archaeology has been defined as “the process of reconstructing the lifecycle of the product – the customer requirements, design specifications, and manufacturing processes used to produce it – to understand the decisions that led to its development” [19]. Educational innovations for teaching the global, economic, environmental, and societal foundations of engineering design through product archaeology with advances in product dissection have been proposed [19]. Integrating the global, economic, environmental, and societal issues in engineering design education is a promising new direction for courses that incorporate product dissection activities. Meanwhile, the effectiveness of integrating product archaeology into product dissection activities in engineering design education need to be tested and further evaluated [19]. Moreover, the results of this initial attempt to expose students to the cultural issues of product design were
113 collected and summarized to provide a baseline for future offerings. In the future, the environmental, societal, and economic issues should also be addressed in engineering design courses using targeted product dissection activities.
ii
References
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+Black/Silver/2613894.p?id=1218339943264&skuId=2613894&srccode=cii_18492716&cpncod e=00-42897516-2&ref=25&loc=BCS
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123 Appendix A
Manual and Cooking Guide
3 4 1
5
1 PARTS IDENTIFICATION 3 1 l a t i g i d a l l a t n a P . 8 1
r e d o p e d n ó t o B . 7
1 1. Lid Release r o p a v e d a r o d a c i d n i z u L 1 2
Button / r o p a v a r a p n ó t o B . 6 1
6
1 3
” e t n e i l a c 2. Handle
e s a g n é t n a m “ e d a r o d a c i d n i z u
L 3. Steam Vent
2 1
/ ” e t n e i l a c e s a g n é t n a m “ e d n ó t o B . 5
1 4 4. Lid
l a r g e t n i z o r r a e d a r o d a c i d n i z u
L 5. Condensation
/ l a r g e t n i z o r r a a r a p n ó t o B . 4
1 Collector o p m e i t l e d r o d a m a r g o r p 7 1
e d a r o d a c i d n I z u L / o p m e i t 5 6. Control Panel
1 1
l e d r o d a m a r g o r p l e d n ó t o B . 3
1 7. Inner Cooking Pot
8 1
o c n a l b z o r r a e d a r o d a c i d n i z u
L 8. Measuring Cup
/ o c n a l b z o r r a a r a p n ó t o B . 2
1 9. Serving Spatula
o t n e i m i c o c e d a r o d a c i d n i z u L . 1
1 10. Steam Tray
l o r t n o c e d o r e l b a T 6
8
7 9
10
0 1
9 7
8
6 Control Panel
r o p a v e d a l o r a h C . 0
1 11. Cooking Indicator Light r i v r e s a r a p a l u t á p s E . 9
r i d e m a r a p a z a T . 8 12. White Rice Indicator Light
18 r a n i c o c e d a l l O . 7 White Rice Button
11 l o r t n o
c 13. Delay Timer Button/ 5
e d o r e l b a T .
6 17 Delay Timer Indicator Light
n ó i c a s n e d n o
c 14. Brown Rice Button/ e d r o d e g o c e R .
5 Brown Rice Indicator Light a p a T . 4
4 12
r o p a v 15. Keep-Warm Button/
e d r o d a l i t n e V . 3 Keep-Warm Indicator Light
3 a j i n a M .
2 16 16. Steam Button/
a p a t a l r i r b a a r a p
1 2 Steam Indicator Light r o d a s l u p n ó t o B .
1 17. Power Button
13 S E T R A P S A L E D N O I C A C I F I T N E D I 15 18. Digital Display
14 3
Figure A-1. Aroma manual [54]
124
6 COOKING GUIDE
RICE APPROX. UNCOOKED WATER WATERLINE COOKED COOKING TIMES RICE INSIDE POT RICE YIELD WHITE RICE: 30-35 Min.
2 Cups 2-½ Cups Line 2 4 Cups
. r a l i c s o n e d e u p a u g a / z o r r
BROWN RICE: 100-105 Min. a
e d s a d i d e m s a l ) 5 1 a n i g á p a l n e ” z o r r A l e d a c r e c A “ a e v ( z o r r a e d s e l b i n o p s i
WHITE RICE: 32-37 Min. d s e s a l c s a h c u m n e t s i x e o m o C . a v i t a t i t n a u c a í u g a n u o l o s s e a c i f á r g a l b a t a t s E
3 Cups 3-½ Cups Line 3 6 Cups •
. r o i r e t n i n é t r a s l e d o d n o f l a e t n e r e h d a i t n
BROWN RICE: 102-107 Min. a
r o d a z i r o p a v n u n e i b o l a t e g e v e t i e c a e d a r e g i l a t r e i b u c a n u e l r a g e r g
WHITE RICE: 34-39 Min. a
e d e t a r t , n é t r a s l e d o d n o f l e n e a r e i h d a e s z o r r a l e e u q o d a t n e m i r e p x e a h i S 4 Cups 4-½ Cups Line 4 8 Cups •
BROWN RICE: 110-115 Min. . n é t r a s l e d e s a b a l a a r e i h d a e s e u q
y z o r r a l e e r o d e s e u q r i n e v e r p a á r a d u y a o t s E . n ó d i m l a y o d a v l a s e d o s e c x WHITE RICE: 38-43 Min. e
5 Cups 5-½ Cups Line 5 10 Cups
l e e l r a t i u q a r a p r a n i c o c e d a l l o a l n e o l r e n o p e d s e t n a z o r r a l e e u g a u j n E
BROWN RICE: 114-119 Min. •
: L I T Ú O J E S N O WHITE RICE: 40-45 Min. C 6 Cups 6-½ Cups Line 6 12 Cups
BROWN RICE: 116-121 Min.
. n i M 0 3 1 - 5 2 1 : L A R G E T N I Z O R R A
s a z a T 0 2 0 1 a e n í L s a z a T ½ - 0 1 s a z a T 0
WHITE RICE: 41-46 Min. 1
. n i M 1 5 - 6 4 : O C N A L B Z O R R 7 Cups 7-½ Cups Line 7 14 Cups A
BROWN RICE: 118-123 Min. . n i M 8 2 1 - 3 2 1 : L A R G E T N I Z O R R A
s a z a T 8 1 9 a e n í L s a z a T ½ - 9 s a z a T
WHITE RICE: 43-48 Min. 9
. n i M 9 4 - 4 4 : O C N A L B Z O R R 8 Cups 8-½ Cups Line 8 16 Cups A
BROWN RICE: 120-125 Min. . n i M 5 2 1 - 0 2 1 : L A R G E T N I Z O R R A
s a z a T 6 1 8 a e n í L s a z a T ½ - 8 s a z a T
WHITE RICE: 44-49 Min. 8
. n i M 8 4 - 3 4 : O C N A L B Z O R R 9 Cups 9-½ Cups Line 9 18 Cups A
BROWN RICE: 123-128 Min.
. n i M 3 2 1 - 8 1 1 : L A R G E T N I Z O R R A
s a z a T 4 1 7 a e n í L s a z a T ½ - 7 s a z a T WHITE RICE: 46-51 Min. 7
. n i M 6 4 - 1 4 : O C N A L B Z O R R 10 Cups 10-½ Cups Line 10 20 Cups A
BROWN RICE: 125-130 Min.
. n i M 1 2 1 - 6 1 1 : L A R G E T N I Z O R R
A s a z a T 2 1 6 a e n í L s a z a T ½ - 6 s a z a T 6
. n i M 5 4 - 0 4 : O C N A L B Z O R R HELPFUL HINTS: A
Figure A-2. Aroma cooking guide [54] . n i M 9 1 1 - 4 1 1 : L A R G E T N I Z O R R • Rinse rice before placing it into the inner pot to remove excess bran and A
s a z a T 0 1 5 a e n í L s a z a T ½ - 5 s a z a T
starch. This will help reduce browning and sticking to the bottom of the pot. 5
. n i M 3 4 - 8 3 : O C N A L B Z O R R
• Want perfect brown rice without the wait? Use the “Delay Timer.” Simply A
. n i M 5 1 1 - 0 1 1 : L A R G E T N I Z O R R
add rice and water in the morning and set the “Delay Timer” for when rice A s a z a T 8 4 a e n í L s a z a T ½ - 4 s a z a T 4
. n i M 9 3 - 4 3 : O C N A L B Z O R R will be needed that night. A
• This chart is only a general measuring guide. As there are many different . n i M 7 0 1 - 2 0 1 : L A R G E T N I Z O R R A
s a z a T 6 3 a e n í L s a z a T ½ - 3 s a z a T kinds of rice available (see “About Rice” on page 15), rice/water 3
. n i M 7 3 - 2 3 : O C N A L B Z O R R
measurements may vary. A
. n i M 5 0 1 - 0 0 1 : L A R G E T N I Z O R R A
s a z a T 4 2 a e n í L s a z a T ½ - 2 s a z a T 2
. n i M 5 3 - 0 3 : O C N A L B Z O R R A
A L L O A L E D O D U R C O D I C O C
O R T N E D A A U G A Z O R R A
R A N I C O C E D S O P M E I T Z O R R A
A E N Í L
N O I C C O C E D S A I U G
6
125
Figure A-3. Panasonic Manual [52]
ii
Appendix B
Dissection Documentations
Bill of Material, Panasonic SR-GO6FG
Artifact Artifact Part Sub Artifact Quantity Description Artifact Mass Material Manufacturing Physical Parameters Name Picture Number of Color (oz) Process Lable1 mm) Label (mm) Label (mm) 2 3 Status Light 1 Control 1 Indicates Yellow 0.275 Composite Wire 1 140 Wire 2 Wire 3 Panel the status of length Length Length Assembly cooking and keeping
warm Cooking Pot 2 1 Metal 4.95 Aluminum Forming Radius Height
Heating 3 Heating 1 Conduct Metal 8.78 Iron Machining Inner 48 Outer 117 Plate Plate heat to Radius radius Assembly inner pot
Heating 4 Heating 1 Convert Metal N/A Iron with Forming Radius 8 Element Plate electricity coating Assembly to heat
Thermal Magnet Bottom 5 Body 1 White 1.32 Steel Stamping Radius 60 Cover Assembly
127 Lid 6 1 Plain cover Transpare 8.525 Glass, Radius 85 without nt Plastic, vent or Steel steam hole
Housing 7 Body 1 Silver 11.98 Forming Radius Height 132 Assembly
Outer Panel 8 Control 1 White 0.43 Plastic Molding Height 85 Width 70 Panel Assembly
Status Light 9 Control 1 Cover the White 0.14 Plastic Molding Length 46 Height 49 Cover Panel status light Assembly and fix the wires
Switch 10 1 Connected Black 0.715 Plastic + with actuation lever
Plug Cord 11 1 Black 3.18
Actuation 12 Control 1 Connected Metal & 0.46 Length 104 lever Panel to switch Withe Assembly
Handle 13 Body 2 On sides of White 0.225 Plastic Molding Assembly the housing
Spring 14 Temperature 1 Support the Metal 0.135 Steel Extrusion radius 18 height 40 sensor temperature assembly sensor
128 Screw 1 15 2 Connecting Metal 0.04 Steel Rolling Height 12 with nuts heating element to electrical wire Screw2 16 2 Connect Metal 0.04 Steel Rolling Height 10 Outer Panel
Screw3 17 2 Bottom 0.045 Steel Rolling Height 10 cover Screw4 18 2 Connect Metal 0.035 Steel Rolling Height 12.5 handle to housing
Screw5 19 2 housing Metal 0.03 Steel Rolling Height 8
Screw6 20 1 Heating 0.045 12 plate to housing Temperature 21 1 Senses the Metal, 0.96 Composite Forming Radius 36.5 Height 26 Sensor temperature yellow Assembly of heating plate
Control 22 1 White, Panel Metal Assembly
129
BOM: Aroma ARC-150SB
Artifact Artifact Part Sub Quantity Description Artifact Mass Material Manufacturin Physical Name Picture Number Artifact of Color (g) g Process Parameters Lable1 (mm Label (mm) Label (mm) ) 2 3 Outer 1 Case 1 Connected with Black N/A Plastic Molding Height 110 Lengt 90 Control Assembly inner control and h Panel panel and White indicates the functions and options to choose from
Cooking Pot 2 1 Nonstick Metal 357.5 Aluminu Forming Radius 120 Heigh 144 cooking pot, m with t removable. Coating
Heating 3 Heating 1 Conduct heat to Metal 395.0 Iron Machining Inner 20 Outer 340 Plate Plate cooking pot Radius radius Assembly
Heating 4 Heating 1 Convert Metal N/A Iron with Radius 8 Element Plate electricity to Coating Assembly heat
Inner 5 Body 1 White Steel Stamping Upper 133 Lower 110 Housing Assembly Radius Radiu s
Lid 6 1 Sealed cover Black Plastic, Molding Radius 133 with rubber, Rubber handle and steam vent
130 Case 7 Case 1 Silver Steel Forming Radius 132 Heigh 206 Assembly t
Inner 8 Center 1 White 40.4 Length 83 Width 58 Control Control Panel Assembly
Control 9 Center 92.3 Length 101. Width 61 Board Control 5 Assembly Control 10 Center 1 Cover the White 54.6 Plastic Molding Length 120 Heigh 62 Widt 64 Board Cover Control Electrical t h Assembly Boards
Temperature 11 1 Connected with Black 15.2 Plastic + Upper 24 Lower 48 Heig 19 Sensor actuation lever Radius Width ht Assembly
Thermal 12 N/A Resistor Steam Vent 13 Lid 1 Sub artifact of Black 3.18 Assembly the lid, let the steam out while cooking and collects cooled down steam.
Condensatio 14 Case 1 Collect the Black 13.8 Plastic Molding Width 12 Lengt 61 Heig 85 n Collector Assembly accede steam h ht while cooking
131 Condensatio 15 Case 2 Removable Transpa 13.2 Plastic Molding Width 21 Lengt 70 Heig 51 n Collector Assembly cover of the rent h ht Cover steam collector
Spring 14 Temperat 1 Support the Metal 5.3 Steel Extrusion radius 32 height 37 ure sensor temperature assembly sensor
Screw 1 15 1 Connect Metal 1.3 Steel Rolling Height 16 Radiu 7.5 Condensation s Collector with
Case Screw2 16 2 Connect Outer Metal 1.5 Steel Rolling Height 12 Radiu 8.5 Control Panel s with Inner Control Panel Screw3 17 1 Connect Metal 0.9 Steel Rolling Height 11.5 Radiu 6.5 Condensation s Collector to Case
Screw4 with 18 2 Connect Control Metal 1.1 Steel Rolling Height 10.5 Radiu 6.5 one nut Board Cover to s Inner Housing Screw5 with 19 2 Connect Blue Metal 1.5 Steel Rolling Height 11 Radiu 6.5 two nuts Wire and Black s Wire 2 to Heating Element Screw6 with 20 1 Fix White Wire Gold+ 2.2 Steel + Rolling + Height 10.5 Radiu 6.5 Brac 22.5 Bracket and Black Wire White Plastic Modling s ket to Case Leng
th L-shape Iron 21 1 Connect Lid to Metal 2.0 Steel Forming Length 30 Width 14.5 Bar Housing
132
DSM of Panasonic SR-GO6FG
DSM of Panasonic SR- GO6FG
Status Light Inner Pot Heating Plate Heating Element Bottom Cover Lid Housing Outer Panel Status Light Cover Switch Plug Cord Temp Sensor Assembly Actuation lever Handle Spring Screw 1 with nuts Screw2 Screw3 Screw4 Screw5 Screw6 Wire 1 Wire 2 Wire 3 Status Light Inner Pot Heating Plate 1 Heating Element 1 1 Bottom Cover Lid Housing 1 1 Outer Panel 1 1 Status Light Cover 1 1 Switch 1 Plug Cord 1 1 Temp Sensor Assembly 1 1 Actuation lever 1 1 1 Handle 1 Spring 1 1 Screw 1 with nuts 1 1 Screw2 1 1 Screw3 1 1 Screw4 1 1 Screw5 1
133 Screw6 1 1 Wire 1 1 1 Wire 2 1 1 Wire 3 1 1
DSM For Aroma ARC-150SB
Pot
with one nutonewith
shape Iron Bar
-
Outer Panel Control Cooking Heating Plate Heating Element Inner Housing Lid Case Inner Panel Control Control Board Control Cover Board SensorTemperature Assembly Thermal Resistor Vent Steam Condensation Collector Condensation Collector Cover Spring 1Screw Screw2 Screw3 Screw4 Screw5 with nuts two Screw6 with Bracket L White Wire 2 White Wire Blue Wire Black Wire Black Wire 2 Outer Control Panel Cooking Pot Heating Plate 1 Heating Element 1 Inner Housing 1 1 Lid Case 1 1 Inner Control Panel 1 1 Control Board 1 1 1 Control Board Cover 1 1 1 Temperature Sensor Assembly 1 1 1 Thermal Resistor 1 1 1 Steam Vent 1 Condensation Collector 1 Condensation Collector Cover 1 1 Spring 1 1 Screw 1 1 1 Screw2 1 1 Screw3 Screw4 with one nut 1 1 1 1 Screw5 with two nuts 1 1 Screw6 with Bracket 1 L-shape Iron Bar 1 1 White Wire 1 1 1 1
134 White Wire 2 1 Blue Wire 1 1 1 1 Black Wire 1 1 1 Black Wire 2 1 1 1 1
3
FCM of Panasonic SR-GO6FG
Status Light Status Pot Inner Plate Heating Element Heating Cover Bottom Lid Assembly Temp Sensor Housing Outer Panel Cover Light Status Switch Plug Cord lever Actuation Handle Spring 1 Wire 2 Wire Wire Connect to Electricity 1 Switch Power On/Off 1 1 Convert Electricity to Heat 1 1 1 Chanel Heat 1 1 Conduct Heat 1 Sense Heat 1 Indicate Cooking Status 1 1 1 1 Automatically Keep Warm 1 1 1 Transmit to User 1 1 Cleanable Inner face 1 Non-Stick Surface 1 Cool-touch 1 1
135
llector
FCM Aroma ARC-150SB
Outer Control Panel Cooking Pot Heating Plate Heating Element Inner Housing Lid Lid Release Button Lid Rubber Seal Lid Handle Case Inner Control Panel Control Board Control Board Cover Temperature Sensor Assembly Thermal Resistor Steam Vent Condensation Co Condensation Collector Cover Spring White Wire White Wire 2 Blue Wire Black Wire Black Wire 2 Connect to Electricity 1 1 Switch Power On/Off 1 1 1 Initial Setting of Functions 1 1 Brown/White Rice Option 1 1 1 1 1 Programmable Steam Option 1 1 1 1 1 Keep Warm Option 1 1 1 1 1 Delay Timer Option 1 1 1 Convert Electricity to Heat 1 1 1 1 Chanel Heat 1 1 1 Sense Heat 1 1 1 1 Regulate Electricity based on Temp 1 1 1 1 1 1 1 Automatically Keep Warm 1 1 1 1 Digital Display 1 1 1 Manual Input 1 1 1 Cool Touch 1 1 Condensation Collecting 1 1 1 Transmit to User 1 1 Cleanable Inner face 1
136 Non-Stick Surface 1
ii
Appendix C
Students’ Answers to the Assignment Question 9-11
Student 1
Model: Sanyo ECJ-N55W
9:
Different functions:
Soup/Porridge : lower temp for a longer time Only half of the heat inputs are used; eliminate by a switch on the front panel. Temp Sensor: One group has a temp sensor without magnets; there is a piece of metal that connects different circuits based on temp.
10:
Suggestions:
Size: There is a lot of internal empty space, remove it. Aesthetics: More units would be sold if it were more visually appealing. Variable Temp: metal control
11:
The rice cooker accommodates different cultural needs by allowing many different foods to be cooked. (Porridge, vegetables, etc.)
Limitations: Words printed in English.
Student 2
Model: Aroma Rice Cooker, 8 cup cook touch rice cooker, non-sticky inner pot, one touch operation
9:
138 Other rice cookers had magnetic temperature sensors which was different than ours. It was achieved at a certain heat a magnet would be connected to turn off the warming function of the rice cooker. Also some rice cookers did not have vents but a dome shaped top to catch the steam and not vent it out.
10:
The design of our rice cooker can be improved with a better quality of materials such as the non stick (non-sticky) pot having a better non stick coating. Also more cooking options and different choices to how to cook your rice. The heating mechanism seemed to be simple enough but would have to be changed if more cooking options are introduced.
11.
Our rice cooker seemed to be for an American cultural with its basic rice cooking option and vents to help with the American fasted paced lifestyle such as bulk since we could hold 8 cups of rice which may seem like much but at a cultural aspect Americans are people who eat food in bulk. Overeating and wasting tons of food.
Student 3
Model: Sanyo ECJ-N55W
Removable steam vent, porridge/soup function, steaming tray, keep warm function, one- touch controls.
9:
Other functions:
Porridge/soup function –low power for a longer time Steam tray for vegetables- place above rice when cooking
10:
Suggestions for improvement: make more compact, more aesthetically pleasing.
11:
139 It allows for other food to be cooked so it is not aimed at one culture.
Student 4
Model: Rival CKRVRCMO63: 6 cup cooked capacity, non-stick removable inner pot, keeping warm, indicator light.
9:
Makes Porridge: maintains a lower temperature for a longer period of time. This works the same way as the keeping warm function on our cooker, except keeping different temperatures.
Steamer: steams food. A tray/dish can be placed over the rice pot. It has small holes in the bottom that allow steam through from the rice pot.
10:
The top could be made by plastic or something that retains heat better than glass. More functions could be added. This cooker only cooks and keeps warm.
A higher power could be used to cook the rice faster.
11:
This cooker cooks rice and does nothing else. It is designed to be cheap and have only basic functions. If the user only wants to cook plain rice to accompany their meal, this cooker is adequate.
Student 5
Model: Sanyo rice cooker ECJ-N55W
Porridge soup function, steaming tray, keep warm function, one-touch controls.
9:
Different functions:
Porridge/ soup function: low power for a longer time
Steaming stray for vegetables, place above rice when cooking.
10:
140 Suggestions for improvement: smaller size for the amount of rice it makes, more pleasing to the eye.
11:
Cultural needs: allows for different types of food to be made, so it is more culturally specific.
Student 6
Model: Aroma ARC-733-INGR
Makes 2-6 cups of rice, vegetable steaming stray, and dishwasher safe removable bowl.
Keeping warm setting.
9:
Other Function:
Steaming functions Soup heating Button latches to hold lid on Multiple heat settings
These functions are achieved by adding specific elements to the rice cooker. For example, the steaming function, a separate steaming tray is added to steam vegetables. For multiple heat settings, multiple circuits are introduced that control the amount of current flowing through the heating element.
10:
Design improvements:
Have both heating element circuit connections be thrown in the back. The second connections uses as separate nut instead that was difficult to hold or grab in assembly.
11.
Cultural accommodations
141 Our rice cooker was able to cook multiple types of rice by adding a steaming tray and a non stick coating. Some rice need to be only steamed which is able to be accomplished with this tray. However, It can only run on a 120 V 60 Hz power supply, so this would not be used in
Europe or other places that use a different power supply system.
Student 7
Model: Aroma ARC-733-1NGR
9:
One model uses steam to gasket to pressure cook the rice. The gasket is attached to the lid of the cooker and contains the steam. The group with the gasketed lid also has a vent that releases the pressure when the rice is done.
10:
Our rice cooker should use indirect cooking methods such as steam cooking to prevent rice from burning and sticking in the cook pot. This could be done by installing a sealing gasket in the lid of our cooker and using a separate heater for the cooker.
11:
Our rice cooker is designed with almost no adjustment for different types of rice and would most likely be best for one type of rice.
Student 8
Aroma ARC-733-1NGR
9:
Some rice cooker you can set cooking time or the type of rice you can use. Some can choose whether you want dry cooked rice or porridge.
Some rice cooker has a microcomputer to control the cooked interval. (Cooking time ). It has one compact circuit to adjust the power of heating element by controlling the current flowing through it. It is a more complicated design.
142 10:
1. Our model has a steam tray to steam food. But the space is limited. I hope they can design the outer pot taller and contains double space for steaming. 2. Change a lid with vacuum layer so that it will keep rice warm longer.
11:
It’s a simple designed and cheap kind of cooker with limited usage. It can be used for many sort of rice. But can only cook it one way. (Other cultures may have various ways to cook rice.)
Student 9
Aroma ARC-914B
Cool-touch, 8-cup, one touch operation.
9:
Looking around the room I was able to see different mechanisms associated with each rice cooker. One rice cooker had a little metal tray on the top in which vegetables could be placed in and steam cooked along with the rice, which I thought was really cook and useful because I love steamed vegetables. Another cooker had a lot of different settings and controls opposed to our rice cooker that just simply has an on/off switch. Just about every other rice cooker in the room uses the magnets as a temperature sensor alone so they don’t have the luxury of a warming device along with the temperate control.
10:
To improve our design I would change the material used on the outside of our rice cooker to a material that doesn’t easily conduct heat. That way the rice cooker would get hot on the outside when it is in use. Another improvement that could be implemented would be to have different heat settings so the rice cooker could be more versatile.
11:
143 Our special rice cooker does not really accommodate different culture needs because our rice cooker only cooks rice at the same temperature and the same way. Knowing what we discussed in class we learned that each different type of rice is very different from one another, therefore each type of rice should be cooked differently. So our rice cooker is designed for your basic style white or brown rice.
Student 10
Aroma ARC-914B
One touch operation cool touch body+lid. Removable condensation collector, ensuring light+ fluffy rice.
Non-stick inner pot
9:
Some rice cookers could steam vegetables which were achieved via an extra porous pot.
Another rice cooker could cook soup and had variable temp settings which were achieved with multiple temp sensors.
10:
I suggest to remove the locking lid and replace it with either a glass lid/cover or a steel cover lid. This will make washing easier, be easier to manufacture, and have a more appealing appearance.
11:
It can supposedly cook brown or white rice but the cooker temperature sensor cannot be modified after manufacturing .This does not allow any other types of rice to be cooked.
Student 11
AROMA ARC-7306
One touch operation, cook up to 10-cups, steam rack.
9:
144 Aroma, top of the line, brown rice, white rice, steam power buttons.
These functions are achieved by a microprocessor to electrically control the heating elements.
Rival, Bottom of the line, cook and keep warm switch.
All other models were the same as ours.
10:
Improve the design with options like LED lights, timer controlled, Housing material could be changed to a material that doesn’t absorb any heat.
11:
The rice cooker doesn’t really accommodate many different cultural needs due to the many different ways the rice can be cooked. Also many of the other cultures are poor poverty people and they don’t buy accessories they cook with items form natural surroundings. There are more expensive ones that high end users can buy for different types of rice.
Student 12
Panasonic Rice Cooker # SR-906FG
9:
Other cookers use pressure systems to help cook rice by using licking lids. Other rice cookers also have more functions for cooking the rice.
10:
In my option the rice cooker is pretty good for being a bottom of the line model. I can’t see much that can be done without increasing the price.
11:
Since our cooker only have an on/off switch, it is pretty general and would be able to cook most rice in a normal fusion.
145 Student 13
Aroma ARC-9148 cool-touch body and lid, cooks 4 cups of pre-cooked rice.
9:
One group’s rice cooker has the ability to be able to cook soup therefore it needs four sensors instead of the tow in our rice cooker. Another group’s uses the steam generated from cooking the rice to cook vegetables placed in a tray above the rice.
10:
One suggestion to improve our rice cooker would be the ability to steam vegetables like the other’s groups rice cookers b/c most people don’t eat rice alone. So being able to cook rice and vegetables at the same time would be convenient.
11:
Our rice cooker accommodates different cultures by being able to cook different types of rice like white rice, brown rice, wild rice, and rice mixes. The box and manual are written in both
English and Spanish which, makes their product easily able to be used by more people.
Student 14
Aroma: ARC-730G
20 Cups 1 touch operation
9:
1. Options for steaming or delay timer. 2. Options for certain types of rice (such as white/brown rice) 3. An LED projector of lights
A microprocessor inside to rely the friction of button touching to tell the cooker what
to run at.
10:
1. More options like different settings for different rice, delay timer 2. The LED lights the newer version has.
146 3. A more specific temperature sensor to show temperature on the outside instead of warm and hot.
11.
Some are designed for specific cultures more than others are because some are cost effective which allow for people with quick and easy purposes like in the US to easily cook their rice for a cheap price. Then there are the more expensive rice cookers doe those who eat rice more often such as in Asia and these more high tech options have outside buttons such as changing which type of rice is used and allows for ore differentiation between users.
Student 15
Aroma ARC-733-INGR
One-touch operation, automatic, 4-cup capacity.
9:
other cookers have delay timers, and different settings depending on the type of rice being cooked. For theses features, their cookers are programmed to be set at different temperatures and amounts of time.
10:
Other units have more functions to cook different types of rice. They can cook more cups of rice at a time. A lot of them had more functions the just cooking basic rice.
11:
Our rice cooker doesn’t accommodate different cultural needs discussed in class. It cooks basic white rice so it’s made for American cooking styles.
Student 16
AROMA ARC-733-INGR
6-cup rice cooker & food steamer
9:
147 The other group’s cooker uses steam for cooking rice. It has a gasket coat of a thing. Also when the rice is cooked, It has a vent for the steam to release.
10:
The material used in the pot was probably iron or so. So after cooking rice for about 20 minutes in it, the outer pot may also be hot and may burn someone’s hand. Instead they should use plastic or something like that instead of iron.
11:
It is designed for only one specific type of rice.
Student 17
Aroma ARC-733-INGR
6-cup, steaming attachment.
9:
A rice cooker could contain an extra pot for food steaming. It would sit on top of inner pot and utilize excess steam. It can also function as a steam/pressure cooker Soups and stews could be heated.
10:
The wiring inside our rice cooker was tangled and hard to disassemble/reassemble. If wires were organized more neatly the internal design would be much cleaner. Materials used seem to be the bare minimum and cheap but that is expected from a mass-produced machine.
Temperature sensor is simple but functional. Could be changed.
11:
Rice cooker can steam any kind of rice, which caters to many cultures. It also allows for preparation of other vegetables, etc. Using the same steam energy at the same time. This all-in- one method is beneficial for poorer nations/ time- restricted meals.
Student 18
148 Panasonic SR-GO6FG
9:
Some cookers have electronic temperature sensors. Some have more advanced lid, allowing quicker cooking time, as well as pressure release valves.
10:
The only thing I could see that could be improved on this cooker, while still keep it cheap is to create a nicer lid for it, sealing things better.
11:
Since our cooker only has an on/off switch, it is pretty general and would be able to cook most rice in a normal function.
Student 19
Panasonic Model SR-GO6FG
9.
All the cookers are essential the same. The only thing that is really different is user interface, steam release/pressure cooking, and “ cool touch” features.
10.
for being as cheap as it is, there isn’t much you could do to improve it. Pressure cooking would take a major redesign, and from what we are told it cooks rice and keeps it warm quite well. Therefore, I would not really change anything about it.
11.
The rice cooker was not really made with cultural diversity in mind; it cooks rice a certain way, and does it quite well.
Student 20
AROMA ARC-733 1NGR
9.
149 Other cookers have the choice of cooking different type of rice and delay timer. These are achieved by a program downloaded on a chip in the machine.
10.
Improvements for our cooker would be a way to cook a variety of rice, a large pot, and a better quality cooking pot.
11.
The cooker does not accommodate types of rice. There is only one setting.
Student 21
AROMA ARC-733-1NGR
9.
One other model has two separate coils. One coil is for warming and both come on to cook the rice, this model is also capable of cooking porridge/soup. The heating is changed, some rice cookers have steaming tray, which sits atop the pot, and is covered with the lid.
10.
A lid with a pressure. Regulated function would make the cooker more efficient.
A plastic housing or some from of insulation cook make the housing “cool to touch”.
11.
The rice cooker only cooks in a certain temperature it cannot be adjusted. The plug is designed to be used in the U.S.
Student 22
Aroma ARC-733-1NGR
9.
Some types have a steaming tray that sits above the cooking pot and allows foods to be steamed while rice is cooking.
150 One group’s rice cooker has a setting for soup/porridge. The heating is changed for this setting. Current passes through only one of the two heating elements.
10.
The housing is made of metal so it can heat up and cause finger burns. The model could incorporate a could touch housing. ( I think they are made of a low conducting plastic.) Functions could be added to cook soup/porridge. The device warms automatically when plugged in, so it could be left on easily. Maybe incorporating an ”off” button would be safer.
11.
The device only cooks to one temperature, so no accommodation there. It has a steamer.
It only works on 60hz so not good for European market. It has two-prong plug which can be used in South America too. The instruction manual is in several different languages.
Student 23
Rival “CKRVRCM063
10:
Better lid to keep heat in. lid with a handle.
Steamer.
More power to cook faster.
11.
Multiple languages on lid and manual.
Cook multiple types of rice.
Non-threatening design.
Student 24
Aroma ARC-914B
8-cup, Cool touch housing, non-stick inner pot, one-touch operation.
151 9:
They had different temperature sensors and different steam collectors. They are achieved by the use of different components.
10:
The rice cooker can have a heavier bottom to prevent getting knocked over easily. The rice cooker can have a steam collector the moves the steam of for it is done cooking to prevent an exhaust of steam especially once done cooking.
11:
The rice cooker can have the “cook”, “keep warm” function which seems universal. But there are not specific function designed to meet the needs of cooking different types of rice