Quality Improvements Towards Zero Defects

Home , Six Sigma, Total quality management, Zero Defects

Addressing the Implementation Gap Between Industry and Literature

PAPER WITHIN Production Systems AUTHOR: Gabriella Gustafsson & Wiktoria Rydin JÖNKÖPING June 2020

This exam work has been carried out at the School of Engineering in Jönköping in the subject area Production System with a specialization in production development and management. The work is a part of the Master of Science program. The authors take full responsibility for opinions, conclusions and findings presented.

Examiner: Carin Rösiö

Supervisor: Gary Linnéusson

Scope: 30 credits (second cycle)

Date: 2020-06-03

Abstract

Abstract Customers today demand products of high quality, and industries must cope with issues related to that to stay competitive. Therefore, an endeavor to achieve zero defects and to work with zero defect manufacturing (ZDM) is common in industries today. ZDM aims to reduce the number of failures within a manufacturing process and thus only producing faultless products. Since defected items result in unexpected work, extra costs, claims and unsatisfied customers, it is important to avoid that in order to secure the company’s market share. Even though it implies challenges, companies must work with ZDM and quality tools to stay competitive. However, there is a gap between the literature of ZDM and how to accomplish ZDM in practice, which makes it hard for companies to apply the method. Hence, this thesis aims to address this gap and present how the human factors and quality contribute to the goal of zero defects. When working with a manually driven manufacturing setting, human factors must be considered as an important aspect. Mistakes will occur as long as humans work with the products, but the prerequisites for doing right must be as good as possible to be able to decrease the number of mistakes. Another factor to consider is the internal quality of different processes to ensure that customer demands are achieved through all stages. This study focused on finding suggestions for improvements towards zero defects in manual assembly and to present general improvement actions. The thesis is based on three main fields: ZDM, quality and human factors. The findings are connected both to literature searches made within these fields, but also through a case study at the focal company. In the analysis chapter, the reader is provided with information about how the specified problem areas are linked together and to the three main fields. By combining the literature search with a case study at a focal company, findings could be detected, collected and analyzed. Four areas could be identified in the analysis and highlighted in the discussion of the research questions. The highlighted areas were further used as a foundation to establish suggestion within the important areas. These acts as practical guidelines for how to reach zero defects in an existing production with the goal of minimizing the implementation gap of ZDM.

Keywords Zero defect manufacturing, Quality, Human factors

Acknowledgment

Acknowledgment We would like to start by expressing our gratitude to the people who have helped us along the way. First, we would like to thank our supervisor Gary Linnéusson at School of Engineering in Jönköping, for guidance and support throughout the project. Moreover, we would like to thank the focal company for the opportunity to belong to their project and be provided with information and inestimable inputs. A special thanks to Nina Ström, our supervisor at the focal company, for all help and support.

Contents

1 Introduction ...... 1

1.1 BACKGROUND ...... 1

1.2 PROBLEM DESCRIPTION ...... 2

1.3 PURPOSE AND RESEARCH QUESTIONS ...... 3

1.4 DELIMITATIONS ...... 3

1.5 OUTLINE ...... 3

2 Theoretical Background ...... 5

2.1 ZERO DEFECTS ...... 5

2.2 QUALITY ...... 6

2.2.1 Total Quality Management ...... 7 2.2.2 Supplier Quality ...... 7 2.2.3 Internal Quality Assurance ...... 8 2.2.4 FMEA ...... 8 2.3 HUMAN FACTORS ENGINEERING ...... 11

2.3.1 Human Error ...... 12 2.3.2 Situation Awareness ...... 14 2.3.3 Acknowledgment and Responsibility ...... 16 2.3.4 Factors Affecting Human Performance ...... 16 3 Method and Implementation ...... 18

3.1 RESEARCH APPROACH ...... 18

3.1.1 Link Between Methods and Research Questions ...... 18 3.2 LITERATURE REVIEW ...... 19

3.3 CASE STUDY ...... 21

3.3.1 Case Company ...... 22 3.4 DATA COLLECTION ...... 22

3.4.1 Disruption Poll ...... 23 3.4.2 Instruction Failure Poll ...... 23

III

Contents

3.4.3 Survey Assembly Instruction ...... 23 3.4.4 Documentation of Observation Data ...... 24 3.4.5 Documentation of Claim Data ...... 24 3.4.6 Competence Assessment ...... 24 3.5 IMPLEMENTATION ...... 25

3.5.1 Fishbone Diagram ...... 25 3.5.2 5 Why Analysis ...... 25 3.5.3 FMEA ...... 26 3.6 ETHICAL CONSIDERATION ...... 26

3.7 VALIDITY AND RELIABILITY ...... 27

4 Findings and Analysis ...... 28

4.1 LITERATURE REVIEW ...... 28

4.2 CASE STUDY ...... 29

4.2.1 Introduction for new employees ...... 29 4.2.2 Disruption Poll ...... 29 4.2.3 Instruction Failure Poll ...... 30 4.2.4 Survey Assembly Instruction ...... 30 4.2.5 Documentation of Observation Data ...... 31 4.2.6 Documentation of Claim Data ...... 31 4.2.7 Competence Assessment ...... 32 4.2.8 Summary of Case Study Findings ...... 32 4.3 IMPLEMENTATION ...... 33

4.3.1 Fishbone Diagrams ...... 33 4.3.2 5 Why Analysis ...... 34 4.3.3 FMEA ...... 35 4.3.4 Summary of Implementation ...... 35 4.4 ANALYSIS ...... 36

5 Discussion and Conclusion ...... 39

5.1 DISCUSSION OF METHOD ...... 39

5.2 DISCUSSION OF GENERAL ASPECTS ...... 40

Contents

5.3 DISCUSSION OF FINDINGS ...... 40

5.4 CONCLUSIONS ...... 45

6 References ...... 47

7 Appendices ...... 51

7.1 APPENDIX 1 – DISRUPTION POLL AND RESULT ...... 51

7.2 APPENDIX 2 – INSTRUCTION FAILURE POLL ...... 53

7.3 APPENDIX 3 – SURVEY ASSEMBLY INSTRUCTION ...... 54

7.4 APPENDIX 4 – OBSERVATION DATA ...... 57

7.5 APPENDIX 5 – CLAIM DATA ...... 58

7.6 APPENDIX 6 – COMPETENCE ASSESSMENT ...... 59

7.7 APPENDIX 7 – FISHBONE DIAGRAM ...... 60

7.8 APPENDIX 8 – 5 WHY ANALYSIS ...... 62

7.9 APPENDIX 9 – FMEA FORM ...... 63

Introduction

1 Introduction This section will present a background to the problem of this study. Furthermore, a problem description, purpose and the study’s research questions will be presented in this chapter. Finally, the delimitations and the outline are stated.

1.1 Background To meet the customers' demands in the industry today, high quality is needed (Chahar, Hatwal, & Sen, 2019). If a product fails to keep what it promises, the customer is likely to complain. In today’s society with easy access to social media, it can have enormous consequences, for example loss of customers. Therefore, it is of great importance for the manufacturing companies to ensure the quality of the products and to have as few defected items as possible, maybe more important now than ever. A company that succeeds in having high-quality products is more likely to keep its customers and to be recommended for others and, in that way, attract new customers (Patel S. , 2016). To ensure high quality products within a company and increase the competitiveness of the company, several different aspects must be taken into consideration (Gewohn, Usländer, & Beyerer, 2018). One aspect to consider is the initial raw material used for the products, which must be of high quality in order for the finished product to have the possibility to meet the demands. Moreover, the workforce must have high skills and be supported by experts when needed (Chahar, Hatwal, & Sen, 2019; Dreyfus & Kyritsis, 2018). Further, there needs to be an established knowledge and understanding within the company of how the products fit into the market and how they will be used (Gewohn, Usländer, & Beyerer, 2018). Companies that successfully meet the customers’ need and expectations of the products’ quality by working in a systematically and innovatively way, often gains competitive advantage compared to companies that do not do that (Bergman & Klefsjö, 2007). Quality management can be found as early as during World War II in The United States when so-called quality gurus revolutionized the attitude towards quality by highlighting its significance (Patel S. , 2016). Moreover, in 1970, Japanese companies got a huge competitive advantage in the industrial market by improving their industries according to the customers’ requirements and expectations. The effects of these changes caused some industries in the USA into bankruptcy, due to changes in the market’s expectations (Bergman & Klefsjö, 2007). All this by moving the focus to the customers’ requirements and expectations (Bergman & Klefsjö, 2007). Similar, according to Patel (2016), quality improvements were included in the manufacturing process in the early twentieth century. Regardless of the long involvement of quality in the manufacturing industries, challenges of how to manage quality optimizations still exist. The quality of a product is not only affected by what happens inhouse, but is also greatly dependent on a company’s suppliers and their contribution and knowledge about quality (Noshada & Awasthib, 2015). Moreover, the technical tools must maintain durability and high quality to create faultless products (Fakert, Gromov, Muller, Polzer, & Wolf, 2008). Further, continuous improvements in machinability and more advanced

Introduction technical tools are desirable factors that contribute to the quality of the products (Fakert, Gromov, Muller, Polzer, & Wolf, 2008). Another fundamental aspect to consider in manual production, when speaking about quality, is the human effect on the different operations (Ostadi & Masouleh. S, 2019). As long as the assembly is driven by humans, errors and defects will occur and cannot be entirely avoided (Wickens & Hollands, 1999; Guastello, 2013). However, several things can be done to prevent errors caused by humans, for example by making clear guidelines and by using correct tools effectively, the number of errors and defected products can be minimized. Today there are various established methods available to analyze, improve and confirm the quality of a company, for example failure mode and effect analysis (Xiuxu & Yuming, 2010), fishbone diagram (Tongyuan, Chao, & Lixiang, 2018) and zero defect manufacturing (Eger, et al., 2018), depending on the desired outcome. Examples of desired outcomes could be minimizing waste, minimize defected items or decrease the number of customer claims. Customer claims result in unexpected work, extra costs and unsatisfied customers, which companies want to avoid. Therefore, zero defects and zero defect manufacturing (ZDM) are important strategies to be able to prevent and predict scrapped parts and failures in the production system (Eger, et al., 2018). ZDM is an efficient strategy when striving for zero defected items (Psarommatis, May, Dreyfus, & Kiritsis, 2019). To achieve zero defects in a manual production may seem impossible, but there should be an endeavor towards perfection within the quality of both products and processes (Psarommatis & Kiritsis, 2018). The situation at the companies has changed over time and with new technologies, such as computer-based data storage, the zero defect manufacturing (ZDM) has been enabled (Psarommatis, May, Dreyfus, & Kiritsis, 2019). ZDM is a strategy that aims to reduce and mitigate failures within the manufacturing process and the goal is to remove defected items in production (Psarommatis, May, Dreyfus, & Kiritsis, 2019; Dreyfus & Kyritsis, 2018; Eger, et al., 2018). For a company to be more environmentally friendly and to maintain an effective assembly with zero defects, the standard of ZDM is the way to go (Psarommatis, May, Dreyfus, & Kiritsis, 2019).

1.2 Problem Description Due to challenges in quality assurance that companies face today, an interest in finding efficient ways towards increasing and maintaining high quality is essential. There are many areas affecting the work to gain and maintain the quality the customer asks for, such as controls and human factors (Malega, 2016). Thus, several different aspects must be considered, evaluated, and identified in order for the company to know how to stay competitive and develop end-product quality (Zhu, Alard, & P, 2007). A potential implementation gap was identified between the theories about how to accomplish ZDM, resulting in no claims, and how to manage that in an assembly in practice. Even though the theory present solutions and guidelines applicable for companies, it was sometimes difficult to implement them due to a lack of generalizable instructions. Thus, this project aims to identify how the gap can be supported by 2

Introduction collecting empirical data from a case company and shows how the literature can support the journey towards zero defects. Also, how these areas could be improved to be able to meet the target of zero defected items in a general assembly.

1.3 Purpose and Research Questions The project aimed to address the identified gap between the literature and the ZDM implementation in an assembly in practice by identifying key factors that affects the output and the work towards zero defects. Therefore, the research questions were: 1. Which problem areas can be specified within the goal of zero defects in the assembly? 2. Which of the specified problem areas can be identified to have the most effect of the goal of zero defects? 3. How can the specified problem areas be supported by the suggested improvements?

1.4 Delimitations This project was limited to one case containing one company in which one cell and one line was examined. When collecting data, other cells and lines at the focal company were not taken into consideration. Covering the entire assembly would have required much work and this was not possible to include within the timeframe of this project. Therefore, the case findings were restricted to focus on one cell and one line to get a realistic and informative result which can be applied to the other assembly units. Even though the case focused on two different assembly units, i.e. one cell and one line, the information will be combined to one analysis, to simplify the result and discussion. Since the goal of zero defects is rather extensive and involves many different areas and aspects, the focus of the study was limited to the research fields of ZDM, quality and human factors. Thus, areas like for example financial aspects, choice of production systems and external factors is not considered.

1.5 Outline The thesis is based on five main chapters with several contributing subheadings. In chapter one, an introduction of the subject and background are presented to provide the readers with the positioning of the study as well as the identified knowledge gap. Moreover, the study’s research questions are presented together with the purpose and delimitations. The second chapter, theoretical background, begins with a literature review including a pre-study, presenting relevant theories to further encircle the scope of the study. The pre-study is then followed by a more detailed literature search of the scope in order to support the discussion and conclusion of the research questions and build a foundation for the case study. The third chapter, the method and implementation chapter, describes and presents motivations to the structure of the theoretical background and how it was conducted. Furthermore, the overall approach of the study is explained, and a guide of the order to which the research questions are supposed to be answered. Further this chapter also motivates and describes the implemented 3

Introduction methods used to analyze and collect data of the conducted case. The method chapter is then followed by the findings from the project, i.e. the fourth chapter, where the linked analysis related to the findings also are presented. In the fifth chapter a summary and a discussion of the gathered data, method and result will be presented as well as a discussion regarding the realistic effects of this study. Other relevant information can be found in the appendices.

Theoretical Background

2 Theoretical Background This chapter presents relevant theories and methods needed to understand as well as to establish a foundation for the project. The main focus areas are zero defect manufacturing, quality and human factors, which then are divided into subheadings for a clearer understanding.

2.1 Zero Defects Zero defect manufacturing (ZDM) is an efficient strategy towards an assembly that delivers zero items with defects (Eger, et al., 2018; Psarommatis, May, Dreyfus, & Kiritsis, 2019). The purpose of ZDM is to reduce the number of errors and faults in the manufacturing process which in turn will result in a more cost-efficient, environmentally friendly and competitive production process (Psarommatis & Kiritsis, 2018). As a result of the improved manufacturing process, ZDM is also related to other benefits, for example less scraped output, faster lead times and deliveries, resilience towards problems, increased planning abilities and confidence in availability and output quality (Lindström, et al., 2019). Similarly, Bai & Zhang (2018) highlights several advantages of ZDM, and the concept’s contribution towards a significant reduction of the costs of the company’s defective products. The concept contains four elements: detect, predict, repair and prevent and they can be seen in Figure 1 (Psarommatis & Kiritsis, 2018). Psarommatis et al. (2019) further describe it as if the defects are detected they can be repaired and the data collected by the defect detection can be used for prediction of failures and to prevent them. Though it seems impossible to achieve zero defects in manual production, the concept strives towards perfection intending to improve the quality of products and processes (Psarommatis & Kiritsis, 2018).

Figure 1 Zero defect manufacturing elements, adapted from Psarommatis et al. (2019) The literature field pertained to ZDM is extensive, and there are many areas and strategies linked to the fundamental ideas of process improvements of ZDM (Lindström, et al., 2019). Furthermore, there is an alignment between the benefits of the ZDM strategy and the ideal industry 4.0 strategy, and thus ZDM can be considered 5

Theoretical Background as a contribution towards an integrated knowledge flow. The flow is established through a combination of different information from multiple systems (Lindström, et al., 2019). One aspect of the theory related to zero defect production (ZDP) or ZDM is a theory by Mycklebust (2013). He presents a lifecycle approach of ZDM to highlight the importance of a combined model, including product quality, resource performance, product-plant view and lifecycle analysis. That results in a model consisting of an extensive knowledge-feedback loop and a collection of real-time data. Moreover, Ostadi & Masouleh (2019) discuss the errors causing the defects in a manual production plant and link them to both human, technology and process-related errors using a failure mode and effect analysis (FMEA). Based on the result from the FMEA, Ostadi & Masouleh (2019) states that the main factor to consider in the work towards ZDP is the human factors, i.e. aspects as stress and lack of motivation. Furthermore, Dreyfus & Kyritsis (2018) describes the importance of monitoring and understanding the humans’ role in the production to maintain the high quality. Moreover, Ferretti, Caputo, Penza & D'Addona (2013) present another action strategy towards ZDP and ZDM constituting of indirect actions, i.e. training of operators, raw material inspection, internal controls and maintenance and direct actions, such as process monitoring. In summary, different factors contribute to zero defect manufacturing and the theory presents strategies for companies to follow. The problem is the gap that occurs between the theories and the company’s implementation of it. Here the theories present guidelines for how to accomplish ZDM, but they are not always easy for the company to follow. However, it can be said that several different factors contribute to zero defect manufacturing, in which there are two central aspects to the concept linking theories together: quality and human factors. These factors will, therefore, be further described in the following chapters.

2.2 Quality Better quality contributes to the success and profitability of a business (Bergman & Klefsjö, 2007). With high quality comes more satisfied customers that are more likely to return and buy the products again, and also recommend them to others (Bergman & Klefsjö, 2007). The emphasis on sustainable production is increasing, and to be able to meet the customer’s demands, it is of great importance to use the resources efficiently (Colledaniab, et al., 2014). Also, to be efficient along the life cycle of the process, product and production is important (Colledaniab, et al., 2014). A strong interaction between quality, production planning and maintenance can be seen and also their relation to so-called production quality, which is described by Colledaniab et al. (2014, p. 773) as “the company's ability to timely deliver the desired quantities of products that are conforming to the customer expectations, while keeping resource utilization to a minimum level”. Still, it is important to remember that quality is a broad expression and includes many different factors and terms.

Theoretical Background

2.2.1 Total Quality Management Total quality management (TQM) is described by Bergman & Klefsjö (2007) as a constant endeavor to fulfill and hopefully exceed the customer’s needs at the lowest cost. To continuously work with improvements and that all involved should be committed are also important. It is an ongoing process of satisfying the needs of the customers and a vital part in generating business profit (Chaudary, Zafar, & Salman, 2015). TQM is built by several management tools and methods which all focus on fulfilling the demands of customers (York & Miree, 2004). This is done by identifying their spoken and unspoken needs, be responsive to the changing market and ensuring the improvement of efficiency in the process that produces products or services (York & Miree, 2004). Supporters of TQM also indicate that an implementation of TQM will have a positive result on the company’s financial performance (York & Miree, 2004). However, a successful implementation and ongoing process of TQM is based on the commitment of all employees and their contribution to continuous improvements and willingness to combat shrink costs and waste (Chaudary, Zafar, & Salman, 2015). All TQM principles are shown in Figure 2.

Figure 2 TQM principles, adapted from Bergman & Klefsjö (2007)

2.2.2 Supplier Quality Maintaining and developing the quality of suppliers are important activities for several different reasons (Noshada & Awasthib, 2015). High quality contributes to lower claim costs and if the claims are low, the customers are more pleased with the products and are more likely to recommend the company to others (Noshada & Awasthib, 2015). One way of ensuring the supplier quality is to use supplier auditing as a tool for quality management (Zulkifli, Abd. Aziz, & Sivalingam, 2015). By a systematic and independent process, evidence for the fulfillment of principles, compliances, green programs and agreed standards can be determined (Zulkifli, Abd. Aziz, & Sivalingam, 2015). As the need for different products changes over time, the sustained quality needs to be assured to keep the end-user satisfied and remain at the market (Walker & Hon, 1988). Another factor described by Malega (2016) as one of the most important key factors to stay competitive is the supplier quality assurance. The supplier quality assurance must not conflict with the company strategies and the company must be

Theoretical Background confident that their supplier delivers what the customer demand in a satisfying way (Malega, 2016). It is further described by Walker & Hon (1988) that supplier quality improvements, which are connected to the supplier quality assurance, are based on three elements: customer commitment, documentation of requirements and introduction of the supplier quality improvements to the suppliers. These elements depend on several factors that differ among different companies and every relationship needs its specialized way (Walker & Hon, 1988).

2.2.3 Internal Quality Assurance At the same time as the quality assurance among suppliers is important, it is also of great importance to ensure the quality within the company. To continuously work with internal quality assurance can be seen as one central factor in order to be successful (Lundgren, Hedlind, & Kjellberg, 2015). Internal quality is connected both to the people and to the group and one must take responsibility in order to succeed (Andriansyaha, Taufiqurokhmana, & Suardi Wekkeb, 2019). When a company deals with humans and not only robot procedures, an understanding of structures and basic morals are vital and contribute to the process of learning how to implement the quality into the work process (Andriansyaha, Taufiqurokhmana, & Suardi Wekkeb, 2019). To ensure the correct product quality, every process and operation must be designed in the best possible way. A more holistic perspective of the quality assurance is needed where it is included as an integrated part of the whole product realization process (Lundgren, Hedlind, & Kjellberg, 2015). Lundgren et al. (2015) further explain the application of a front- loading approach, i.e. most of the work effort is assigned to the planning stage to ensure a careful planning process. It also ensures that problems are detected in an early stage and can be prevented before they occur.

2.2.4 FMEA FMEA stands for failure mode and effect analysis and is a tool within TQM that helps to identify potential failures before it happens (Bergman & Klefsjö, 2007; Xiuxu & Yuming, 2010). It is one of several quality control methods and contains actions to minimize the failure risks within a production system (Burduk & Krenczyk, 2017). The method is used as a systematic review of products, or processes, function, errors, causes and consequences (Bergman & Klefsjö, 2007). Xiuxu & Yuming (2010) describe FMEA as a vital part of a company’s assurance of quality improvement of products and effectivity in manufacturing. The practical application of FMEA is of two different types; product FMEA and process FMEA, and the comparison them between are showed in Table 1 (Kania, Cesarz-Andraczke, & Odrobinski, 2018).

Theoretical Background

Table 1 Comparison of product and process FMEA, adapted from Kania et al. (2018)

Product FMEA Process FMEA Criterion of analysis Fulfillment of utility functions by Correct process realization, the product fulfillment of process requirements Subject of analysis Product, subassemblies, Stage of the process elements (operations, actions, procedures) Asked questions What causes may lead to total What defects may occur in a or partial disappearance of the given stage of the process and product’s function? What what may be their impact on consequences may be the product/construction or associated with them? service defects Examples of defects Element cracking, no medium Wrong connection, breaking flow time, misadvising Examples of defected Construction defects, wear, Machinery/device errors, man causes service errors, environmental mistakes, incorrect methods, impact incorrect material, incompetence, improper work organization Examples of effects Failure/loss of function, medical Nonconformities, lower hazard/danger to life performance, high cost, too long waiting time

Kania et al. (2018) describes two approaches of FMEA that are considered: problems and systematic. Problems are areas where all detected problems are analyzed and activities are selected based on the problem, previous experience, failure analysis, etc. Systematic is an approach where the analysis of the products or processes is made broadly as a system. The first step is to decide the boundaries of the system, and then to identify the subsystems. It is a more generalized approach than the problem approach and it makes the analysis more transparent. The first step of an FMEA analysis is to point out the operations in a process (Malega, 2016). The next step is the identification process of possible defects, followed by a determination of the effects caused by their occurrence and then the possible causes are found (Malega, 2016). These steps can be seen in Figure 3.

Theoretical Background

Figure 3 FMEA activity model, adapted from Malega (2016) When performing an FMEA, pre-defined parameter symbols are used, as shown in Table 2 below, and they represent the numerical values of the terms and are calculated according to the formula given (Burduk & Krenczyk, 2017). Usually the range of 1-7 or 1-10 is used to make the assessment, but it can differ depending on what the analyzing team decides (Burduk & Krenczyk, 2017; Kania, Cesarz-Andraczke, & Odrobinski, 2018; Xiuxu & Yuming, 2010; Valdes, 2015). Table 2 Characteristics of the parameters, adapted from Burduk & Krenczyk (2017)

Parameter symbol Parameter name Description S Severity Whose value is the level of damage effects that occurs in the system O Occurrence The value which represents the frequency of failure D Detectability The ability to detect a potential failure RPN = S * O * D

If the range of 1-10 is used, the value of the risk priority number (RPN) will be somewhere between 1-1000 and a high number of RPN shows a high risk in the process (Burduk & Krenczyk, 2017). If step 3, 4 or 5 from Figure 3 result in high numbers, it means high severity, high probability of occurrence and low probability of discovering the most prioritized failure which has the most serious effect (Malega, 2016). How to assess the severity, occurrence and detectability are described in Table 3, Table 4 and Table 5 (Brassard, Finn, Ritter, & Ginn, 2003). It shows how to analyze the different values based on how much impact it has. When the assessment is finalized and each process has got a value of severity, occurrence and detectability, these three numbers are multiplied and results in an RPN number. The process with the highest RPN number is identified as the highest risk. The full FMEA form used for doing the FMEA is shown in appendix 7.1. 10

Theoretical Background

Table 3 Severity assessment, based on Brassard et al. (2003)

Severity (S) Criteria Value The user will probably not detect the problem 1 Minor impact, the user will notice it as a minor disturbance 2-3 Noticeable impact, e.g. annoying noise or a minor function 4-6 decrease Significant inconvenience which need reparation 7-8 High severity, risk for personal injury or violation of law 9-10

Table 4 Occurrence assessment, based on Brassard et al. (2003)

Occurrence (O) Criteria Value Remote possibility 1 Low probability 2-3 Moderate probability 4-6 High probability 7-8 Very high probability 9-10

Table 5 Detectability assessment, based on Brassard et al. (2003)

Detectability (D) Criteria Value Very low probability that the defect reaches the customer 1 Low risk that the defect reaches the customer 2-3 Moderate risk that the defect reaches the customer 4-6 High risk that the defect reaches the customer 7-8 Very high risk that the defect reaches the customer 9-10 A potential risk with FMEA is that it will not be utilized to its full potential in the manufacturing process (Xiuxu & Yuming, 2010). This problem often occurs due to a lack of relevant and effective management and when a standard for the FMEA knowledge structure is missing (Xiuxu & Yuming, 2010).

2.3 Human Factors Engineering Human factor is a familiar concept that can be traced back to prehistorical times when one first made tools to enhance the capability of performing different tasks in everyday life (Guastello, 2013). Since then, the concept of human factors has evolved and has been transformed into the practice today known as human factors engineering (HFE). The main goal of HFE is to reduce errors, increase productivity and enhance comfort and combability of humans while interacting with a system (Wickens & Hollands, 1999). Another more recent definition of HFE, which has been adopted by this study, is highlighted by Grosse, Calzavara, Glock & Sgarbossa (2017, p. 6901), as “the

Theoretical Background scientific discipline concerned with the understanding of interactions among humans and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance”. Furthermore, it is known that each human has their unique background, which affects their behavior and abilities, not only in their private life but also in the workplace (Wickens & Hollands, 1999). Thus, it becomes important to consider HFE while discussing the quality of products which at some point has been in contact with or developed by humans. Therefore, this chapter will present theories and practices within HFE, which is relevant in order to understand how the different factors in HFE affect the quality and performance of a company.

2.3.1 Human Error When analyzing the performance and quality of a production system or an individual machine, it is necessary to understand the different factors that can affect the outcome. Since human-computer interfaces and human-production units still are active in the industry today, there is a need to consider human error as a factor when analyzing the performance of a system. (Guastello, 2013) Human error is generally divided into five different sub-categories, whereas three of them are related to the personal decision-making and action based on previous knowledge and surrounding information, while the other two categories are related to the timing and order (Guastello, 2013). Table 6 presents an overview of the categories and presents an action example for each error. Table 6 Type of error, adapted from Guastello (2013)

Type of error Definition Example

When operators have the right Commission intention but choose the wrong Pushes the wrong button actions

When operators fail to perform the Forgetting to include or attach Omission needed action parts in an assembly

Extraneous When operators perform unrelated, Fixing something that isn’t acts unnecessary or unconnected actions. broken

Attaching part B before part A, Actions performed in the wrong Sequential when the order should be A and order. then B.

Actions performed too soon or too Timing Operator fails to meet pace late.

Theoretical Background

Similar to the general categories of errors, there is another classification of human errors which is linked to a behavior model separating human errors into three categories which are skill-, rule- and knowledge-based errors (SRK) (Marquardt, 2019). These levels are more detailed described by Cummings (2018) whereas she states that skill-based behavior is defined by highly automatic and sensory-motor actions that have been acquired by the operator through training and repetition. Furthermore, the next level of the model is the rule-based behavior which contains the actions supported by underlaying subroutines, rules and procedures. Finally, the third level, with the highest level of cognition in the model is the knowledge-based actions, where mental models are used by the operators to guide and aid the actions performed. The actions are performed through a deep understanding of the identified problem and previously gained knowledge about the specific task. According to another classification scheme of the human error process, presented in Figure 4 and developed by Wickens and Hollands (1999), the errors are divided into five categories which are linked to three levels of stimulus evidence. Thus, the scheme presents an information processing approach to how humans receive and process information and selects an appropriate action (Wickens & Hollands, 1999).

Figure 4 Classification scheme of Human Errors, adapted from Wickens & Hollands (1999) Moreover, Wickens and Hollands (1999) classify the errors in the scheme as follows: mistakes, which are separated in knowledge-based mistakes and rule-based mistakes, slips, lapses and mode errors. The areas are further described in Table 7 presented below.

Theoretical Background

Table 7 Error classifications, adapted from Wickens and Hollands (1999)

Example of Classifications Definition & Process Shortcomings

Mistakes Incorrect knowledge i.e. • Failure to interpret the Knowledge- wrongly formulated information, displays and based intentions resulting in communications wrongly intended action • Insufficient knowledge or expertise

Rule-based Applied rules are wrong i.e. • Misinterpretation of the wrongly formulated situation and surroundings, intentions resulting in which lead to misapplied rules. wrongly applied rules • “Bad rules” is learned and intended action is wrong (if- applied then)

Slips Intended action is correct • When the right intentions are but incorrectly carried out exchanged for a well-practiced behavior pattern. • Failure to note small changes in work process • Failure to monitor relatively automated action sequences

Laps Failing to carry out actions • Memory problem, at all Forgetfulness

Mode errors Appropriate actions/modes • Failure situation awareness for one operation is applied and understanding of the in the wrong scenario problem

2.3.2 Situation Awareness To further understand the underlying and direct shortcomings resulting in human errors, one factor to consider is situation awareness (SA), which conceptualizes the person’s understanding and integration of the surroundings (Marquardt, 2019). SA has been defined by Endsley (1995, p. 36), as a human’s “perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future”. Endsley (1995) separates SA into three different levels, where the first level is the operator’s perception of surrounding elements, the next level is the comprehension of the situation and the third and final level is the ability of prediction for the future situation. Furthermore, Endsley (2015) describes the relationship between the levels as ascending and not linear stages, which implies that the levels are not necessarily data- driven. Thus can a person for example use the current understanding and projections of a process, level 2 and 3, to generate assumptions regarding level 1 information, both rightly and wrongly (Endsley, 2015). A person who understands the current situation

Theoretical Background has higher SA than a person who has accessibility to all data, but does not understand its meaning (Endsley, 2015). Figure 5 displays the schematic view of a person’s dynamic decision making, where SA is presented as a vital part of the system. The figure also presents the importance of individual experience, cognitive abilities, mental state, environment and complexity of the work task.

Figure 5 Schematic figure of dynamic decision-making including SA, modified from Endsley (1995) The model by Endsley (1995) highlights how the experience, training and abilities supports both the SA and the following decision-making process of a person. Strater & Bolstad (2008) present three conditions needed for a successful SA development for people, which is feedback, repetitive practice and development of an extensive case bank. Furthermore, they highlight the importance of incorporating all the three levels of SA into the student’s training for the employees to understand and perform their tasks correctly. These questions have further been explained and specified by Mason (2020), where for level 1 the question is what, i.e. what do I see/hear, for level 2 the question is so what, i.e. what does it mean for my task, and finally for level 3 it is now what i.e. what may this result be in the future. Similar Chahar, Hatwal & Sen (2019), performed a study and concluded that it is important for a company to focus on employee training in order for the employees to become efficient in their work task, which in turn results in organizational output. Moreover, they suggest that a trained staff contributes to a better organizational climate which further results in increased creativity and learning. Chahar et al. (2019) findings also present that by developing employees’ technical and personal skills and abilities will also result in the enhancement of future learning abilities. Additionally, the personnel’s work motivation, job confidence and motivation for the employees to work in different team constellations will increase.

Theoretical Background

2.3.3 Acknowledgment and Responsibility In order to work with and successfully ensure a stable quality enhancement of the products and within an organization, it is essential to establish a positive human mindset based on participation and individual ownership (Bergman & Klefsjö, 2007). Moreover, Carlzon (1985) presents three key factors for establishing a quality enhancement, which is communication, delegation and education. These three key factors fall in line with the formulation of how to work with the enhancement of quality from Bergman & Klefsjö (2007). They highlight the importance for an employee to feel recognized, have a professional pride related to their work tasks and being premiered for well-performed tasks. According to Bergman and Klefsjö (2007), participation and commitment of the employees can be reached through a mix between delegation of responsibility and authority within the company. The authors also clarify that it is not the amount of work assignments that are important, but instead its importance, significance, level of encouragement and stimulus for the operator. Moreover, Bergman and Klefsjö (2007) created a figure, displaying the results of trusting and not trusting the employees of a company, displayed in Figure 6. It displays that good confidence in the management results in a delegation of work, motivated employees and better result. At the same time the opposite, which means when the management does not have good confidence, controls the employees and the employees lose their motivation, result in an impaired result. The goal of the company is to work according to the good circle and reinvent all processes following the bad circle into the good circle instead.

Figure 6 The good and bad circle, adapted from Bergman & Klefsjö (2007)

2.3.4 Factors Affecting Human Performance According to the model by Endsley (1995) in Fel! Hittar inte referenskälla.Figure 5, different factors can affect the performance of an employee, for example stressors and workload. This section presents theories and information regarding some of these factors. Stress is a widely known concept used to describe the feeling caused by external or internal stressors that usually decrease the human’s performance, attention span, SA

Theoretical Background and decision-making processes (Wickens & Hollands, 1999). Typical stressors that can be found in the workplace, and everyday life, are noise, vibrations, time pressures, bad lighting settings and psychological factors (Wickens & Hollands, 1999). Examples of psychological factors can be anxiety, fatigue or frustrations (Wickens & Hollands, 1999). According to Guastello (2013), is personnel that are working under stressful conditions with uncontrolled and unexpected stressors more likely to display greater negative performance than personnel working in conditions with known stressors. Stressful conditions during work or work-related stress occur when the worker is exposed to high or low pressure and workload, but also challenges that go over their knowledge and coping abilities (Souza‐Talarico, et al., 2020). Furthermore, Wickens & Hollands (1999) presents theories regarding the relation between training and stress monitoring. They state that repetitive training and learning of new scenarios increase the confidence and skill level of the personnel. This in connection to the three levels of human errors earlier presented by Wickens & Hollands (1999), which are skill-rule- and knowledge-based errors. There they state that a clear linear connection of stress- imposed errors is to be found concerning the three different cognitive levels, where highly skilled personnel are less likely to be affected by surrounding stressors then novices. An expert can replace knowledge-based tasks with skill or rule-based decisions and thus minimize the mental resources and focus all resources at the task at hand. By only focusing on the task at hand, the possibilities of making errors is minimized. Another factor connected to stress, which can be both positive and negative for the human performance, is the consequences of workload. When the term workload is connected to areas like boredom, fatigue or sleep loss it usually imposes a negative effect on the performance, but if it is based on an efficient and stimulating effects, it is considered to be positive (Wickens & Hollands, 1999). Passive jobs, or low strain jobs with low workload, are usually defined by low control or with low demands (Souza‐ Talarico, et al., 2020). This results in boredom and unused potential, while active jobs are defined by high demands and high job controls (Souza‐Talarico, et al., 2020). According to Guastello (2013), the physical and mental workload is not only related to the amount of work but also the speed of the work. Thus, it is important to establish an optimal level of workload for the operators to increase the performance and minimize errors. Robert & Hockey (1997) also highlights the importance of understanding the individual factor while discussing workloads, since all humans have their unique limitation.

Method and Implementation

3 Method and Implementation The methodological approach of the study is described in this section. How the research is linked to the method, the case study and literature review is described here and the implementation and analysis. The chapter ends with a discussion about the validity and reliability of the thesis.

3.1 Research Approach The approach chosen for this study was of qualitative and action research character. An action research approach illustrates how the researchers act in a situation and aims to solve two main goals (Lindström, et al., 2019). These goals were to solve the problem and have a contribution to the knowledge, and the action research includes interaction and collaboration with the personnel (Lindström, et al., 2019). Qualitative research is, according to Yin (2016), used when an understanding of how people cope in a real- world setting is needed. Since the topic of this project was strongly related to humans and how they operate and cooperate, this method was suitable for this project. A literature review was conducted in some specified areas with contributing subcategories. The qualitative research also included a case study, which in turn included a current status analysis and a data collection. It was done through polls and information gained from personnel at the focal company. The process of the work can be seen in Figure 7.

Figure 7 Work process

3.1.1 Link Between Methods and Research Questions To be able to fulfill the purpose of the study, three different research questions (RQ) were created. To answer them, a literature review and a case study, which contained of a data collection and a current status analysis, were made. How these methods contributed to answer the different RQ is shown below.

Method and Implementation

Research question 1 – which problem areas can be identified within the goal towards zero defects in the assembly? • Literature review Research question 2 – which of the specified problem areas can be identified to have the most effect of the goal of zero defects? • Literature review • Case study Research question 3 – how can the specified problem areas be supported by the suggested improvements? • Literature review • Case study • Findings By answering RQ 1, suggestions for RQ 2 were provided and the second question was also able to be answered. The information gained from these two contributed to answer RQ 3.

3.2 Literature Review The literature review started with a pre-study which was made to identify different problem areas connected to zero defects. This was followed by a literature search to be able to define and delimit the problem, to gain a deeper knowledge of each subject found and to have theories to base decisions on. To be able to identify relevant search fields, brainstorming was used. The brainstorming process is a method where ideas from different people are spontaneously exchanged to be able to solve a problem (Xianghua, Jiansheng, Fulin, Li, & Quande, 2018). The brainstorming session, together with the pre-study, led to several different areas from which three specific search fields where chosen; ZDM, quality and human factors. Several subheadings within these three fields were also investigated. To further guarantee that all research fields were covered, the snowballing technique and the bibliography review was used, and the information gained was analyzed by coherence, relevance and adequacy (Booth, Papaioannou, & Sutton, 2016; Leedy & Ormrod, 2005). In the selection of relevant topics, related terms and synonyms were also used, considered and included in the research. The research was narrowed down by focusing on literature written from 2000 and forward, with some expectations. This was also done to be able to ensure the validity and reliability of this paper. A representation of the entire process is displayed in Figure 8. The review was mainly based on books and scientific papers, and the sources were found at Jönköping University’s library and through the Scopus database. The pre-study and the literature review were based on different search fields in Scopus, which in turn had specified search terms. All these are listed below.

Method and Implementation

Figure 8 Literature review process, based on Booth et al. (2016). For the pre-study, specified search areas were used within the field of zero defect manufacturing with the following search terms: • Zero AND defects • Zero AND defect AND manufacturing • “Zero defect manufacturing” • “Zero defects” • “Zero defects” AND production Since quality was one main focus area for the project, a literature search on that topic was made. The literature supported already known facts and contributed to new facts that helped the continuation of the research. The Scopus search for all specific topics included the search terms listed below. Quality: • Quality • Quality AND improvement • Production AND quality • “Total quality management” Failure mode and effect analysis (FMEA): • FMEA • Failure AND mode AND effect AND analysis • “Failure mode effect analysis” • FMEA AND production • FMEA AND risk AND mitigation Supplier quality: • “Supplier quality” • Supplier AND quality • Supplier AND effects

Method and Implementation

Internal quality assurance: • Quality AND assurance • “Internal quality” • “Quality assurance” • “Quality assurance” AND lean Since the field of human factors also was a key factor in the research, additional literature searches were made for that area. The Scopus search was narrowed down to theories related to specific fields listed below and begun with the search within the human factor field. Human factors: • “Human factors” Human errors: • Human AND error • Skill AND rule AND knowledge-based AND behaviors Situation awareness: • Situation AND awareness • Situation AND awareness AND manufacturing • Situation AND awareness AND level • Learning AND training AND employees Performance: • Performance • Cognitive AND stress AND performance • “Human performance” AND workload

3.3 Case Study This project contained a case study performed at a focal company. The case study approach was chosen since it contributed to the holistic view of the problem and gave the authors the possibility to collect a lot of information (Patel & Davidson, 2011). The case study started with a company presentation and a company tour, which gave a holistic view of the company, its products and processes. It helped with the understanding of how the focal company was structured and how the working process was organized. This was followed by a deeper understanding of different problem areas at the company. This was an important step to reach the knowledge of where the main problems occurred and was made through information collection from different fields at the focal company. Unstructured and unstandardized interviews were made with the personnel in the assembly, with easy questions, to get a holistic view of their thoughts and feelings of where problems may occur. This was made initially in the project to get a general understanding of them company and its work process. The method of using unstructured and unstandardized interviews i.e. qualitative interviews, enables the respondents to answer freely to the questions, which is a useful method when collecting interpretations and thoughts about a specific phenomenon (Patel & Davidson, 2011).

Method and Implementation

This was followed by a deeper investigation through polls and surveys to be able to detect specific problem areas.

3.3.1 Case Company The focal company used for this project was a company that works within product development, manufacturing and marketing in the lighting areas. The company supported the case study by constructing a project group in which the authors were included. The project group contained of a project leader, which was a quality and environment manager, two production leaders, two team leaders from the assembly, two from customer design adoption, one from quality and one production engineer. Meetings were held weekly in the project group and these meetings also functioned as gates to ensure that the project was following the time frame and the progress. Data was collected from different departments and analyzed both by the authors, but also together in the group where issues were presented and discussed. These meetings constantly guided the project on its way towards the result. To establish the needed knowledge from the focal company, the department of assembly and production was chosen as the unit of analysis in the case study. The assembly at the focal company consisted of multiple manually cells and lines, where the lines produced according to a set takt time and the cells according to the number of orders. Even though the workload and types of produced products differentiated between the assembly settings, i.e. cells and lines, the operators rotated both between the stations and between the areas at the company. This could be problematic since the workers need knowledge within several different areas and products. To get a realistic output from the case, one cell and one line were examined so both similarities and differences of the workers and the structures were accounted for.

3.4 Data Collection The data collection process started with group meetings together in the project group. Through the meetings, it was decided to move forward with polls, surveys and questioners. According to Patel & Davidson (2011), it ensures an accurate information collection of the current situation at the assembly, where the sampled data could be collected from the workers at the actual assembly units. The polls and questioners were made to get accurate information through closed and open questions (Patel & Davidson, 2011). An overview of the problem areas found in the theory and at the focal company, and how they are linked with the data collection of the project, is being displayed below in Table 8.

Method and Implementation

Table 8 Map of the linkage between problem areas and data collection

Problem areas from theory and focal company Literature search Disruption poll Instruction poll failure Survey Assembly Instruction Observation data Claim data Competence assessment

Assembly instructions X X X X X X

Introduction for new employees X X X

Competence of the employees X X X X X

Technical assistance tools X X X X

Supplier quality X X X X

Internal quality assurance X X X X X

3.4.1 Disruption Poll The first poll focused on problems that occurred in the cell or the line. The operators marked every disruption and marked what kind of disruption, for example if it was damage from supplier, mistakes made by an operator or faults in the assembly instructions. The full version of the poll and the result can be seen in appendix 7.1. This was done for four weeks.

3.4.2 Instruction Failure Poll The second poll had more open questions where the operators wrote information about the faults that occurred. It contained information like how the problem or error occurred, what type of error it was, where it occurred, etc. This gave information about the different types of problems and why they happened, which was the information needed to be able to continue the analysis of this problem area. This poll was performed for three weeks in one cell and one line at the focal company. Afterward, the different problems were classified in different categories based on what kind of problem the operators had, and it was done together with specialized personnel who knew what problem could be connected to what category. The full version of the poll can be seen in appendix 7.2.

3.4.3 Survey Assembly Instruction A survey was made specifically about the assembly instruction field. The survey was designed based on the current situation in the assembly at the focal company, suggestions from the project group and collected theory. The questionnaire was structured with yes and no questions and ended with two more open questions. This gave the respondent opportunities to think outside the box and provide input from real- life situations. The survey was distributed to a group of operators from a total of 5 units of the assembly to collect as many results as possible. Moreover, by extending the respondents group, the result was assumed to be more realistic since the workers rotate between the areas. The handout and mix of the operators were made of the team leader, 23

Method and Implementation since they know their staff’s abilities. This to get answers both from personnel with advanced knowledge within the field of assembly instructions, and from personnel that had less knowledge. The survey can be found in appendix 7.3.

3.4.4 Documentation of Observation Data To gain a deeper understanding of errors that occurred in the assembly, which in turn can result in claims to the customers, a collection of the focal company’s observation data was made. The observation data file was provided by the company from their server where they log control data from previous and ongoing productions. The file was created through a summary of all the previous mistakes and errors found at the plant. When an error or mistake occurred in the assembly, a form was filled in that shows who made the observation, where it occurred, a short description of the problem and to what category it belongs. Examples of different categories can be faults from suppliers, material damage or faults in the assembly instruction. Since this project only focuses on one cell and one line, these stations were sorted out and only data from them were analyzed. As described above, the operators selected one category for each fault, and later the authors analyzed and sorted out the information into pre-defined categories. This gave a holistic view of what kind of problems that occurred and what field they belonged to. It also clarified which problem area, based on only these observations, that resulted in most problems for the cell or the line. The data was limited to 2019 since that was expected to give a suitable amount of data possible to investigate. To only focus on 2019 and not earlier also ensured that only relevant faults were analyzed, which made the data more reliable.

3.4.5 Documentation of Claim Data To be able to reach the goal of this study and identify critical areas affecting ZDM, the claim data was of great importance. Thus, the focal company’s database was used to search for documentation of the registered claims reported by the customers. In order to get relevant results, the document was first filtered based on both the year 2019 and the two examined units. The filtration however needed to be revised, due to insufficient results. Therefore, the filtration was restricted to only filtering based on the year 2019, which meant that all lines and cells were included. The resulting output were categorized into categories depending on the identified defects and types of claim. Examples of defects could be incorrect placed part, missing component and incorrectly programmed driver. When the result was sorted out, it was easily seen which categories contained most claims.

3.4.6 Competence Assessment Furthermore, a competence assessment of the workers was made through a poll administrated by the production leaders. The assessment was made to establish a deeper understanding of what knowledge the working personnel possessed. It was done through an anonymous poll, where the competence of drawing, electrical safety and electrostatic discharge (ESD) were listed in three different columns and a line was drawn in respectively row for each employee who possessed this competence. This was 24

Method and Implementation done by the team leader for the cell and the line to get an objective result. The full poll and answers can be found in appendix 7.6.

3.5 Implementation In order to create well-grounded statements and conclusions regarding the root causes of the different investigated problem areas, the collected data was turned into diagrams and graphs, to establish a better overview. The different data collection methods and results were then compared to one another and discussed in the project group. Based on the discussion, problem areas were selected as the focus for prevention work. The decision was based on the results of the collected data. To further confirm the underlying causes of the problems within the chosen areas, fishbone diagrams, 5 why analyses and process FMEA were created. These methods were chosen through discussion within the project group, based on the findings from the literature review and previous knowledge of the team members in the group.

3.5.1 Fishbone Diagram To further understand the different factors within each of the concerned areas, two fishbone diagrams were conducted. The fishbone method, or Ishikawa diagram as it also is called, is a method used for identifying the root cause of a specified problem (Tongyuan, Chao, & Lixiang, 2018). The model indicates the relationship between the problem and its underlying causes through analyzing of relevant factors and its subareas and underlaying reasons (Tongyuan, Chao, & Lixiang, 2018). The problems chosen for further examination were assembly instruction and lapses or mistakes, connected to both the competence of the employees and introduction for new employees. Each problem was then individually discussed based on five different aspects, which were; human, equipment, material, method and management. The result was then transferred into a template for the method to get a holistic overview. The models were then discussed based on assumptions of severity, reliability and occurrences of the individual factors and underlying causes. The models and results can be seen in appendix 7.7.

3.5.2 5 Why Analysis To further understand the underlying causes and problems concerning the assembly instructions, a 5 why analysis was made based on five random errors which occurred the cell and the line. A 5 why analysis is a method used to explore the cause- and effect relationship of a problem with the help of an interrogative approach (Gangidi, 2019). By repeating “why” five times, the origin of the problem and its solutions became clear (Gangidi, 2019). To get a thorough understanding of different rout-causes and their effect, multiple 5 whys was constructed regarding the problem of incorrect assembly instructions. A decision was made by the project group to select the five problems representing a production in practice, which meant not a tempered or tailored decision, to obtain a better result. Therefore, the first five problems, which occurred between the cell and the

Method and Implementation line, was selected without any adjustments. When each problem was identified, the first step was to identify the main error and then move on to ask the first why, which meant asking why this happened. This question was then repeated four times in order to get closer too and uncover the core problem for each error. When the underlying error factor was identified, a discussion was held within the group to find a prevention or solution for each core problem. The full 5 why analysis can be found in appendix 7.8.

3.5.3 FMEA In the assembly, two different failure mode and effect analysis (FMEA) was done. The FMEA was done at the process of assembling a lamp and before the FMEA was started, the authors ensured that the steps in Table 1 were thoroughly reviewed and understood. The selection of lamps was made based on pre-defined criteria, for example the lamp needed to be assembled in a batch bigger than a few lamps to ensure the validity of the FMEA. It was done by the personnel with knowledge of the lamps and the assembly for the analysis to be as accurate as possible. Besides that, a lamp that was not completely new for the operators was chosen. During the analysis, the authors observed the process carefully. Every process step was noticed and written down in the FMEA form. To ensure that no step was forgotten, every process step was viewed several times and the operators explained what was done and how. After that, all possible failures that could occur in every step were discussed and noticed in the form. This was done by the performer of the FMEA, but with input from the operators who knew about the problems. The next step was to analyze the effects of every failure and to assess the severity if they occur. That was followed by an analysis of the cause of the failures and assessment of the occurrence. Also, a check if there were any current control of the steps, and the assessment of detectability of the failure was made. These assessments were done by using numbers between 1-10, where 1 is no risk and 10 is a very high risk. These three numbers for every step were multiplied with each other and resulted in an RPN number. The action with the highest RPN was the action with the highest risk. The FMEA form can be found in appendix 7.9.

3.6 Ethical consideration Research of this kind should evaluate the ethical factors as one vital part of the study (Creswell, 2009). Since the research was included in a project at a company and involves supervisors both from the school and the company, biases are unavoidable. To be able to avoid biases as much as possible, different kinds of data were collected and several different methods were used. All participants in the polls and interviews contributed anonymously and voluntarily. No data about the participants were collected or used and they chose by themselves if they wanted to answer the questions or not. To further ensure the ethical strength of the study, the four ethical aspects for research, described by Patel & Davidson (2011), has been taken into consideration. These aspects describe how to handle information, consent, confidentiality and utilization through an ethical perspective. All data has been managed based on these criteria and the company

Method and Implementation has approved the used data. Also, the final version of the study is published in the database Digital Academic Archive Online (DiVA), which makes it accessible for everyone and contributes to the purpose of input to the society.

3.7 Validity and Reliability To obtain trustworthiness of the project, especially in qualitative research, it is important to ensure the validity and reliability of the study (Williamson, 2002). One way of doing that is by use triangulation. Triangulation in data collection is described by Patel & Davidson (2011) as when a collection of different data is done. Examples of data can be interviews, surveys and documents, and the result from the methods can either show similarities of differences, and both can be equally interesting for the study (Patel & Davidson, 2011). Despite that, it is important to remember that all kind of research is likely to be interpreted by both the authors, but also the ones involved in the study that belongs to the focal company (Gummesson, 2003). Further, Gummesson (2003) describes the research as an upward spiral where data is interpreted and re-interpreted in a never- ending process of trial-and-error including both theory generation and theory testing. To be able to increase the reliability of this research, all research steps can be found in Figure 7 which allows the reader to repeat the study. The chosen methods were carefully selected to suit the explorative approach of this study and ensure the validity, both internal and external. The external validity and reliability were especially supported by the literature review and by adding real-life data from the focal company, the strength of the study could be ensured. The final discussion will be presented in chapter 5.

Findings and Analysis

4 Findings and Analysis This chapter outlines what was found both from the theories and from the case study. Findings from surveys, polls and documents are described separately and a summarize of the finings is also presented. The chapter ends with an analysis of the most important findings.

4.1 Literature Review When striving for zero defects, quality is a holistic expression included in all actions taken towards the goal of no claims. From the theory, ZDM, quality and human factors were three terms that seemed to contribute to the knowledge gap. These three factors were then further analyzed and thus the following factors were founded. Firstly, Endsley (1995) pointed out the importance of creating instructions that makes it easy to do things right for the employees. Similar, according to Wickens & Hollands (1999), good instructions should be clear and leave a small, or non-existing, room of alternatives of how to do things. Another factor applicable to ZDM is the introduction of new employees, both regarding how they should perform their tasks and if they are provided with accurate instructions before they start. According to Endsley (1995) the structure of an instruction and what it contains can be decisive for both the performance and employee’s skill development. In this area, Wickens & Hollands (1999) further describes and classifies errors in different categories and means that several aspects must be considered within a learning process. Mistakes can, for example, be made due to incorrectly formulated information. This means that the operator may not have intended to do the wrong thing, but since the instruction failed, that could be the result. This can further be connected to the employee SA, which was presented by Endsley (1995), where the competence of the individual was in focus. Moreover, the competence focus could also be found within the theories of error classifications presented by Guastello (2013) and Wickens & Hollands (1999), in which certain categories were dedicated to errors with competence related causes. Another factor found in the theory, which was presented as a side-factor to the different theories, was the technical assistance tools for the workers. It was mentioned as a stressor (Wickens & Hollands, 1999) and as a factor affecting the SA (Endsley, 1995). From an external perspective, the suppliers are a vital part of a company. Without a functioning collaboration with the suppliers, the production will be suffering, and it will affect the customers. Noshada & Awasthib (2015) highlight the importance of maintain and develop the quality of the suppliers, and to continuously work with the relation between the suppliers and the company. Further, Malega (2016) describes that when the cooperation works well, it increases the possibilities to stay competitive at the market. The company knows that it can rely on its customers and will be able to deliver what the customers demand. Moreover, the internal quality assurance was relevant for the study. For a company to be successful, Andriansyaha et al. (2019) declares that the internal quality assurance

Findings and Analysis should be a central factor and exist throughout a company’s process. Internal quality assurance involves both the individual and the group, and every employee in a group needs to take responsibility to be able to succeed with internal quality assurance. In summary, these problem areas, which also can be seen in Table 8, were found from the theory: • Assembly instructions • Introduction for new employees • Competence of the employees • Technical assistance tools • Supplier quality • Internal quality assurance

4.2 Case Study At the focal company, findings were collected that both contributed to theories found, but also findings that could not be directly linked to the literature review. The focal company provided the project with relevant information and crucial knowledge. By doing surveys and interviews and have ongoing discussions within the project group, useful data and invaluable inputs were shared, which contributed to the result. These findings are further described below.

4.2.1 Introduction for new employees The company tour, qualitative interviews and presentation of the focal company exposed a lack of routines regarding the introduction of new employees at the company. The introduction of new employees was generally left to the team leaders and production leaders to arrange. There was no verification of drawing skills beforehand, but it was covered with an oral briefing from the team leaders with support from a guidance paper. The description was then supported by a light version of education with the team leader, where the novice got extensive support with knowledge, tips and tricks while working in the line. The extent of the education was different between the assembly units and persons, based on the previous knowledge, skills and abilities of the individual, and the design of the line or cell. Further, the qualitative interviews and the presentation of the focal company together with the data presented a competence deficiency of vital skills among the employees. Moreover, there was no available routine for renewal or introduction to additional relevant skills that the employees could sign up for. This was regulated by the management and inserted when suited.

4.2.2 Disruption Poll The first poll generated a total of 268 logged disruptions during a period of four weeks, which was separated into different categories. Since the poll was created separately in the two analyzed units, each result could also be viewed separately, and the full result can be seen in appendix 7.1. It could be stated that the line had 171 disruption while the cell logged 97 disruption, during the same period. After further discussion with the production leaders, it was

Findings and Analysis concluded that this was to be a true relation between the assembly units and their different production rates. In the line the three areas with the highest number of logged disruptions were: mistakes or lapses, defected product from previous stage, i.e. internally, and incorrect assembly instructions. In the cell however, the three highest recorded areas were: incorrect assembly instructions, material deficiency and unclear assembly instructions. This displays that it was a difference between the two production units, which can be traced back to the unit’s production rate, complexity level and variety of its produced parts. If combining the result of the two production areas, the combined highest recorded categories were lapse or mistake, incorrect assembly instructions and defected product from previous stage. Thus, it can be stated that the categories that caused the most disruptions were connected to the assembly instructions and errors caused internally due to different human errors.

4.2.3 Instruction Failure Poll The second poll, called instruction failure poll, was conducted over three weeks in the analyzed units. It resulted in a total of 33 recorded errors and improvement suggestions for the assembly instructions. Different from the disruption poll was that the unit with the most logged problem was the cell with a total of 20 problems, while the line only logged 13 problems. Once again, this could be explained by, and connected to, the difference in complexity of the produced products. Also, the occurred errors differentiate between the different units. In the line most errors occurred due to balancing of work assignments between the different stations, whereas in the cell the errors occurred due to construction flaws in the products. The full result and the other recorded errors and implementation suggestions can be seen in appendix 7.2.

4.2.4 Survey Assembly Instruction The survey of assembly instructions resulted in answers from 37 respondents. Most of the respondents answered all the multiple answers question i.e. the question with the selection options, but there was a clear lack of answers linked to the open question and the ranking question. The ranking question resulted in 27 responses, i.e. 14 respondents ignored the question. Moreover, the open question resulted in 10 responses. i.e. 27 respondents left it blank. Even though this was the case, the questions were included as a valid result, since the addressed questions were not dependent on the number of respondents. This since the questions were expected to only collect suggestions from the workers and grade pre-selected suggestions based on the workers own assumptions, and not highlighting possible problems. The multiple answers question resulted in company-specific results, linked to the production area of the focal company. However, by generalizing the result and making general conclusions, it could be applicable to other companies and support the theory. One important finding to highlight was the clear connection between the amount of time worked at the company, and the workers’ certainty and ability to perform the job.

Findings and Analysis

This could also be connected to the relation between the workers’ certainty of how to perform the job, introduction and knowledge they had before their time in the production area. Another conclusion made from this survey was that most of the workers stated that they produced at least some percentage of products without looking at the instructions. Thus, if the instructions were to be changed this may pass unnoticed by the workers.

4.2.5 Documentation of Observation Data The observation data gained from the focal company showed the spread of the faults in the assembly. A total of 164 observations were analyzed and all observations were connected to one cell and one line and occurred during 2019. What resulted in the most observations was the personnel and handling category with 73 observations. Within that category it could be seen that 63 out of 73 was connected to faults from previous stage, i.e. internal faults. It can also be seen in the other categories that faults from previous stage was a factor connected to several of the total observations, more specific 83 % of the observations could be linked to faults from previous stage. All results can be found in appendix 7.4. The result was presented and discussed in the project team and an action plan for this was created. It was also further evaluated together with the result from the disruption poll. The disruption poll showed that the highest amount of disruption was connected to lapses or mistakes caused by humans, which goes in line with the result from the observation data. Therefore, the project team decided to make a fishbone diagram. The fishbone diagram was made on lapses and mistakes and could be linked to both faults made in the line or cell, but also to fault from previous stage. The full result from the fishbone diagram is further discussed later in this thesis. As Andriansyaha et al. (2019) describes, internal quality is important for a successful production and it is connected both to the people and the group. Every individual must take responsibility, but the processes and operations must also be designed in a way that enables the operator to do things right (Lundgren, Hedlind, & Kjellberg, 2015).

4.2.6 Documentation of Claim Data Information about the focal company’s claims could be collected from an internal system, where information like what type of claim, why it resulted in a claim and to which department the claim belonged to could be found. When the claim analysis was done, all claims from the assembly department at the focal company was investigated. This was made to be able to see if any pattern in the claims could be found, and to ensure a fair picture of the result. The claim data were sorted into eight different categories, for example handling damage, incorrect or incorrectly placed part and not followed drawing. This was made to get a better overview of the different types of claims that occurred. A total of 133 claims was reported for 2019 and 55 of them were connected to the category incorrect or incorrectly placed part. The second most frequent claim was connected to the category not followed drawing, with 25 reported issues. In third place was the category

Findings and Analysis missing component with 17 reported problems. The full result can be found in appendix 7.5.

4.2.7 Competence Assessment The competence assessment of the employees in the two units was conducted on a total of 26 people, including the current working team leaders of the two areas. The assessment was made for one day, which meant that not all the operators in the two different areas were there to answer the poll. Despite this, it was assumed to be representative for all the workers based on an assumption made by the team leaders and therefore resulted in a valid result. In the line, there were 12 respondents, whereas one person had the competence of drawing knowledge, one of electrical safety and 11 had the electrostatic discharge (ESD) knowledge. Moreover, in the cell it was 14 respondents whereas two people had the drawing knowledge, five had knowledge in electrical safety and 12 with ESD-knowledge. Based on the result, which can be found in appendix 7.6, it can be stated that there was a critical knowledge gap in the workforce. Based on the facts about the critical knowledge gap and lack of educational possibilities for the employees together with the almost non-existing introduction for the new employees, it is safe to say that there is a need for development within these areas. The result from this competence assessment can be connected to the theories presented in the theoretical framework. Chahar et al. (2019) highlights the importance for a company to focus on continuing development and to work towards a well-educated workforce. This is also further explained through the SA theories and the human error classifications presented by Endsley (1995), Wickens & Hollands (1999), Guastello (2013) and Marquardt (2019) where the connection between the different models, training and competence can be linked to different errors made by humans.

4.2.8 Summary of Case Study Findings When collecting data at the focal company, one relevant factor found was the assembly instructions. Though it seems to be easy to have accurate assembly instructions, the investigations showed the opposite. The assembly instructions were unclear, messy, contained too much information or the wrong information. The operators at the focal company participated in a survey about assembly instructions and more about that can be seen in chapter 4.2.4. Internal quality assurance was another critical factor found. It may seem obvious to work with internal quality assurance, but it was shown at the focal company as a main factor of disturbance. A lot of the faults made internally were also detected internally so it did not result in claims at the customer. Still, it was one of the factors which resulted in the most disturbances and problems within the cells and lines when a poll was done. Another identified factor to consider while discussing ZDM is the competence of each employee at the workplace. Based on the findings at the focal company, a lack of competence was found together with a lack of systematic education of the personnel.

Findings and Analysis

Furthermore, it was found that there was no clear routine of how the novices should be introduced to the different assignments during the introduction of new employees. Instead, the introduction was delegated to the team leaders of each line and the production leaders of the assembly. Thus, the length, depth and content could vary between different persons. Moreover, it was found that the only regulation used today at the company was a guidance paper of important subjects for the instructors and a decision of a light version of education between the team leader and novice. Also, there was no need for the novice to attend any tests or education to ensure their competence. Further there were two additional factors found in the literature review which were not found as critical at the company. The two factors technical assistance tools and supplier quality were found at the case company but did not have the highest number of occurring errors based on the collected data. Thus, the factors were filtered out before the implementation chapter. Moreover, it was found that the errors linked to supplier quality were related to external factors, i.e. supplier production errors, transport and construction errors. They were therefore excluded from this case. Similarly, the importance of technical assistance tools was in the theories, but it was hard to measure and analyze at the company. The factor technical tools was however continuously considered throughout the project, but was seen more likely to be included as a solution for preventions than as an origin to error. In summary, these problem areas, which also can be seen in Table 8, were found from the case study: • Assembly instructions • Introduction for new employees • Competence of the employees • Technical assistance tools • Supplier quality • Internal quality assurance

4.3 Implementation From the findings mentioned above, actions were taken during the case study, and different methods were tested and implemented. All methods were based on theories and discussed in the project group to ensure the relevance of the implementation. These actions and methods are further described below.

4.3.1 Fishbone Diagrams Two different fishbone diagrams were made. The fishbone was based on five different factors; human, equipment, material, method and management. Below each factor, underlying problems detected by the team were listed. The first diagram was made on mistakes or lapses. By brainstorming in the project team, the problems connected to each head factor were identified and discussed. Issues connected to humans were for example stress, loss of focus and lack of knowledge. Examples of issues connected to the material category were unclear assembly instructions and material that were delivered to the wrong place or in the wrong amount. From these findings, discussions were held with experts in the areas of issues. The 33

Findings and Analysis discussions lead to specified action plans, one for every issue, with the purpose of clarifying how to improve and solve the identified problems. Holistically seen, lack of focus, knowledge and stress together with lack of controlling the work done of the operators, are factors that summaries the faults that often occur. Also, the fact that faults easily can be done by the operator without being detected was an important factor to consider while trying to make improvements. The second fishbone diagram was made on assembly instructions. The underlying factors from this diagram, connected to humans, were for example competence, lack of ownership and introduction. Lack of ownership means that the operator does not feel any responsibility or ownership for the product, which results in a lack of motivation for doing things right since it will not affect the operator itself. As described earlier, every human has their unique background, and this will also affect how they behave and what abilities they have. To become successful as a company and ensure a high quality, a positive human mindset based on participation and individual ownership is needed. As presented by Bergman & Klefsjö (2007), an employee needs to feel recognized, have a professional pride related to their work assignment and being rewarded for well-performed tasks. Since this was detected as a problem, actions were created to further increase this for the operators, to be able to decrease the issues. Issues connected to the management factor were for example company culture and that operators may not help each other with issues. This can also be linked to the importance of participation of the employees and their backgrounds and behavior. The full results from the fishbone diagrams can be seen in appendix 7.7.

4.3.2 5 Why Analysis The 5 why analysis resulted in a diagram where the identified problem was described followed by the answer to each of the five why questions where it was applicable. Further, possible actions were stated to correct and prevent similar errors. Four of the identified problems were directly connected to errors in the drawing and structure of the product. Of these, two were linked to human factors, i.e. stress, workload and inadequate training of new constructors, whereas one was linked to a lack of defined routines and personnel accountability. Moreover, the fourth and the fifth error could be linked to process errors. One was linked to the translation between the internal systems, i.e. between the systems used, and the active system used for the work instructions on the monitors for the workers. The second was due to the lack of routines for changes in structures for active products. Even though the underlying problem variated, the main area could be connected to the routines of the management. The addressed routines were linked to either the company’s work process or workload balance. Based on the result of this analysis, there is a need for more sufficient support for the workers, i.e. stricter routines, instructions, training and guidance, to prevent similar errors from occurring. The full table can be seen in appendix 7.8. Based on the findings from this analysis, together with the theories of stress, workload, performance and SRK, it can be stated that there was a need of increasing the staffs’

Findings and Analysis training and knowledge to minimize the errors. By increasing the training, introduction and employee’s SA, the staff can shift from making knowledge-based errors to rule- based errors. Further, these improvements are theoretical assumed to results in a lowered mental workload and individual pressure and thus minimize the error occurrence.

4.3.3 FMEA Two different process FMEA were done, one on assembling a lamp in a cell and one on assembling a lamp in a line. The purpose was to find out if FMEA could be suitable to use as a method when for example start the production of a new process or product. When analyzing the faults from the FMEA, the RPN number was the factor of interest. The steps with the highest RPN should be seen as the highest risks in the assembly and therefore most interesting to look further at. Several faults were discovered in the FMEA that may not be discovered before. What also could be seen through the FMEA was that most of these faults were not controlled in later steps. This means that if they occurred, it was not likely that they would be discovered at all. The result of that would be a claim at the customer, which was to be prevented. From the FMEA, one process step that resulted in a high RPN was when a cable was not assembled correctly and resulted in disconnection. This may not be discovered in a light test but could still be a problem later when the lamp does not light up and the customer reclaims it. Another process step revealed was the difficulty in fastening screws with the right torque. This may result in broken components and rework, or components that must be thrown away. With help from the FMEA, problem areas were discovered that would not have been detected otherwise. If FMEA is used as a tool in an early step of the process, faults are likely to appear and can be prevented before they occur. In that case it would not affect the production or the customer. It is a way of ensuring the stability and quality of the process towards a ZDM. The highest scores from the FMEA can be found in appendix 7.9.

4.3.4 Summary of Implementation After the fishbone diagrams were made, it could be seen that a lack of knowledge, decreased focus and stress among the workers were the most frequent faults that occurred. Also, issues connected to the management and the company culture were found. Participation and individual ownership together with education would be critical to improve these areas. From the 5 why analysis the need of increased training and knowledge of the staff were found. This was similar to what was found after making the fishbone diagrams and strengthen the hypothesis of needed improvements within these fields. The FMEA resulted in several different faults. Even though the detection of faults was interesting, the authors found it more interesting to investigate if FMEA could be used as a tool in the beginning of a new process. Since faults were discovered that most likely

Findings and Analysis would not have been discovered otherwise, it can be stated that FMEA may be helpful in the start-up process.

4.4 Analysis After collecting all findings described above, next step was to sort out the most important information and convert it into useful action plans. This process started with an analysis, seen in this chapter, and ended with discussion and conclusion in the following chapter. The literature areas of competence, skill and abilities of the employees are extensive. Through the findings from the literature review and the data collection, they have been shown to play a vital role in the process of quality improvements and ZDM. Moreover, the competence of the employees can be linked to the introduction of new employees. Hence, to improve the competence, skill, abilities of the personnel and further improve the overall motivation and mentality in the workforce, regulated routines are necessary. This, in connection to the theory which states the importance of a good SA within a group, and that it starts from the basic understanding i.e. the introduction of new employees. After comparing the result from the case study with the literature, an implementation gap was found. When analyzing the output, both the data collection and the theories connected to human factors showed potential for improvements. Thus, in order to prevent problems associated with human errors and to create a structured routine for handling the employee’s competence, a few suggestions of process implementations were made based on the theories. It was suggested to implement a training station where no products that will end up at the customers will be produced. By implementing a training bench, where new employees must practice on performing different operations and handle different situations, the overall SA would be improved, especially the first and second level, i.e. perception and comprehension. Further, it also will affect the third level of SA by establishing a deeper knowledge of the products and possible implications of different actions. According to the theory of human errors, the development of individual SA also contributes to mistake prevention and decrease the mental workload by exchanging knowledge-based decisions to skill- or rule-based decisions. Another suggestion related to this area was connected to the employee competence development, in which the suggestions was to implement yearly courses in necessary skills. Further, the suggestion was to restrict the time of the validity for the courses to ensure that the skills are renewed and up to date. This to minimize slips and mistakes related to both the memory and SA, but also to increase the confidence and personal development, which further affect the motivation and mental environment at the company. By improving the competence and mindset of the workers, an improvement of the work in group constellations and the overall performance at the company is assumed to increase. By ensuring that every individual knows what to do and to make sure that everybody has the same information, the trust between the workers can increase. It will also remove unnecessary disruptions, and thus positively affect the transparency within the workforce.

Findings and Analysis

A connection between human factors and internal quality assurance can also be seen. Internal quality assurance is strongly connected to motivation, mindset, responsibility, ownership and routines. An operator who feels motivated at work, have a mindset influenced by positive thoughts and have a feeling of responsibility for the assignment, is more likely to perform well. With support from the management, support from correct and clear routines and with a feeling of ownership for the products that are produced, a desirable result can be expected. This is showed in Figure 6 and supported by Bergman & Klefsjö (2007) in the good and the bad circle. Internal quality assurance can also be connected to some of the TQM principles shown in Figure 2Fel! Hittar inte referenskälla.. One TQM principle is that everybody should be committed, which is a vital part of the work with internal quality assurance. If every worker feels a commitment to their work, they are more motivated to do things right and tend to feel a responsibility. Moreover, they strive to be accurate in the work process and are motivated by doing things right. Also, the TQM principle about base decisions on facts can be connected to internal quality assurance. If clear guidelines and correct facts are presented, it left no room for misunderstandings or options and all decisions that need to be taken can be motivated by instructions or facts. It closes the option to discuss what was done and why, and instead ensure that everyone does what they are supposed to do. Internal quality assurance has been mentioned several times through the thesis and was an important concept in the project. At the focal company it was found that several disturbances could be connected to faults made internally in previous stage. It could for example be the wrong number of items delivered to the line from the storage, which resulted in extra orders and unnecessary waiting time. Another thing was faults made in another department that resulted in parts that were not able to be used for production, which also gave unnecessary waiting time. Further, this could lead to delays in the delivery to the customer. All this pointed at a lack of internal quality assurance. Moreover, mistakes were made by the operators in the lines and the cells that sometimes were detected by other operators. This was not always the case, but it could be seen that if some sort of extra internal control was implemented, most of these faults were able to be discovered before the product went to the customer and claims could, in that way, be prevented. These areas were analyzed and discussed in the project group and seen as fields of improvement. Based on findings made and discussions held in the project group, it was suggested to make tests of how the internal control in a line and a cell could be better ensured. Since the prerequisites do not look the same in a line as in a cell, two different suggestions were presented. In the cell, it was suggested that additional controls should be added to the assembling process. The control should contain an ensuring by the operator that the drawing, the BOM-list and all instructions were followed correctly. This should happen at three points. First, when a new order is to be started, second, at every rotation of the employees and third, when the last part of every order is assembled. In the line, a different approach was chosen. It was recommended to have an additional station that would work as a control station. This station was placed where the product was

Findings and Analysis assembled as much as possible, but when there still was an opportunity to check all critical components and assembling steps of the product. Another aspect to consider was the assembly instructions. To design an assembly instruction in a way that ensures that everyone understands, but without containing too much information, is a challenge. As mentioned several times before, accurate and structured instructions is crucial for an operator to accomplish the work and to assemble a correct product. The opposite, i.e. a messy and unclear instruction, obstruct the work and increase the risk of produce defected items. From what was seen about the assembly instruction, the idea of using FMEA was raised. The suggestion was to use it in the introduction phase of a new product in the production. When starting the production, the FMEA could be used to detect problems or uncertainties in the instructions. A mixed group with both operators and personnel from other relevant departments should be created to ensure that all relevant aspects are considered. From the analysis, the instructions could be improved and corrected, and a better instruction could then be presented. This would prevent faults from happening and ensure that the instruction suits the production. From the survey made about assembly instructions, findings about what operators considered as a good instruction was found. Suggestions were made based on the answers and with influence from the theory. According to this, a good assembly instruction should contain: • Clear guidelines with relevant details, i.e. dimensions and pictures connected to the drawing • Pictures of how to assemble critical steps • A picture showing the result after the product is assembled correctly and in its correct environment • A BOM-list structured in the way the product should be assembled • Verification after making all steps A combination of the suggestions above would increase the ability of the operators to applicate the instructions into the work and produce a faultless product. To ensure that would in turn result in fewer claims at the customers.

Discussion and Conclusion

5 Discussion and Conclusion

This chapter summarizes the thesis with a discussion about the method chosen and a discussion about the findings. The research questions are answered here and finally a conclusion and suggestions for further research are presented.

5.1 Discussion of Method The approach chosen for this study was of qualitative character to ensure a deep and thorough insight into the field of study (Williamson, 2002). The risk with qualitative research is that the generalizability decrease, and to prevent that, the methodological approach was carefully chosen. That also ensured a high validity and reliability and increased the generalizability. The project included a single-case study performed at a specific company. To only use a single case instead of multiple cases, affect the possibility of generality negatively. The generalizability of the project has been an important aspect to consider and discuss throughout the project, and to be able to ensure that, some actions were taken. Even though it was decided to only use a single case, the procedures carried out in the study were described in an accurate and detailed way to ensure that the readers understood and could follow the steps. The single-case study guaranteed a depth in the data collection since the authors’ focus were limited to one case only, and not divided between several different cases. This ensured that all information presented was carefully evaluated and analyzed. In the selection of respondents at the focal company, the team leaders helped the authors to select a suitable group based on their knowledge about the employees. A risk with this kind of selection is that the answers are biased. To avoid this, a collection of employees from different departments, and by different team leaders, were chosen to minimize the risk of subjective results. A literature search was conducted and over 100 articles were reviewed carefully, which strengthen the generalizability of the study. Even though this was done, it was hard to ensure that all relevant literature for the specific fields were reviewed. By using the snowballing technique and the triangulation it ensured that the risks decreased (Leedy & Ormrod, 2005). The triangulation also increased the validity and reliability of the study (Williamson, 2002). Due to lack of time, only suggestions for improvements could be provided and no implementations of these suggestions. This means that the result of the suggestions could not be evaluated, but from the careful way all suggestions were analyzed and discussed, they are based on well-founded decisions. By controlling all collected data with the supervisors at the focal company and compare it with the theories, subjectivity in the study were avoided. Together with the triangulation, it ensured that the quality of the data increased.

Discussion and Conclusion

5.2 Discussion of General Aspects Since this thesis was performed in collaboration with a company, the problem investigated was created based on a goal in their organization. Hence, the company initially presented problem areas that were to be investigated and analyzed throughout the project, which they assumed would result in interesting results. They also delimited the project to two assembly units, which meant that no other assembly units could be investigated. Thus, it can be argued that the problem definition was designed to solve the company’s problem and that the project was influenced by that. This can be seen as a weakness both for the reliability and the validity of the project and was carefully taken into consideration. Therefore, it was of great importance for the authors to not be affected by the company’s desire, but instead find theories to base the decisions on. Another aspect related to the company providing suggestions for areas to focus on, is that the search field in the theory was possibly broadened. Since the different suggested areas was taken into consideration and investigated in the theory, different perspective for similar problems was identified. This resulted in identification of aspects extending over multiple areas, which otherwise could have been missed due to lack in information presented in the theory. To be able to minimize the risk of getting biased, frequent meetings and discussions with the supervisor at the school were held to ensure that the project kept the right direction. Even though the supervisor could affect the direction of the project based on his knowledge and interpretations, it was expected that the requests from the company together with the authors’ work and help from the supervisor, ensured a balance in the report. Throughout the project, the authors strived to ensure that the theoretical contribution was fulfilled by relying on theoretical facts from the theories to identify important areas. Hence is one of the theoretical contributions for this study the anchored suggestions within the specific areas. The other contribution is the highlighting of the identified areas, both within the theory and by the verification at a company, which works as a guidance towards ZDM.

5.3 Discussion of Findings The purpose of this study was to minimize the gap between the knowledge of the factors affecting ZDM according to the theory and how they can be implemented in a real-life assembly. Moreover, the study was supposed to present a more generalized guidance on how to improve critical factors towards a ZDM. Thus, this chapter will present a discussion based on the study’s findings in connection with each of the research questions, which will end in an answer for each of the questions.

Discussion and Conclusion

Research question 1 – which problem areas can be specified within the goal of zero defects in the assembly? To be able to answer the first question, a literature review was conducted in which the literature regarding zero defect manufacturing (ZDM) and zero defect production (ZDP) was presented. Moreover, the findings from the literature review presents three critical areas affecting the company’s output, i.e. ZDM, human factors and quality. These areas needed to be further analyzed to establish more detailed critical factors and thus minimize the identified gap. By analyzing the connection between quality and human factors to the presented elements of ZDM, a few assumptions and decisions could be made that later was used as a guide for the rest of the study. By firstly investigating the area of quality, it became clear that the existing theory presented various methods which could be applied to improve a company’s overall quality. Moreover, it was discovered that the field of quality was rather extensive, resulting in that the sub-areas not linked or considered related to ZDM were filtered out. The focus of the search was therefore placed on areas highlighted in the pre-study of ZDM, which were quality assurance, supplier quality and relevant quality concepts, like FMEA and TQM. Even though the areas are slightly different from each other, they can all be linked to the triggering elements of the ZDM model, seen in Figure 1. The areas were considered to fall within the prevention element of ZDM, due to changes and actions taken during the applications. Within the areas of maintenance and quality, there were two areas found in the theory: external and internal controls. The theory emphasized the importance of continuous and extensive controls of both physical objects as well as virtual data in different systems. For example, it could be control of a production process, information on QR-codes or thoroughness of assembly steps in the production units. Since there was a connection between all the researched area in the ZDM theory, the model and an assumed realistic connection were further investigated. Based on the theories, it was displayed that the areas mentioned, i.e. supplier quality and internal quality assurance, were to be considered as two main factors. This since it was linked to quantifiable data and was presented to play a vital part in the work towards ZDM. Secondly, the other main area found in the pre-study was the extensive area of human factors, which includes underlying factors of errors, factors affecting the person and their performance. In the ZDM theory, human factors were highlighted as a vital part of the work towards zero defects, especially when discussing manual assembly. This since as long as there are humans involved in processing a product, there will be an effect on the result, i.e. visible mistakes, forgetting to include parts, inadequate controls, and lapses. The area of human factors was considered to fall in both the prediction and prevention elements of ZDM. Based on which orientation of analyzes that is chosen, analyzes of errors could both be used to predict new errors as well as highlight possible prevention methods. Based on this, a decision was made to further research the area of human factors, which resulted in a deep dive into the human factors engineering (HFE) area. Similar as in the processing process of the quality area, unrelated or badly linked sub-areas of HFE were filtered out from this study. The filtration of relevant areas was 41

Discussion and Conclusion established based on assumptions and decisions made by the study’s authors and were based on the area’s relevance to ZDM. Thus, there may be overlooked factors that could have resulted in another outcome and orientation of the study. Linked to human factors and the HFE, many areas were presented as important to manage and consider in order to reach a zero-defect assembly. Moreover, most of the theories presented in the theoretical background are interconnected to one another or are a concept developed based on previous work. One example of this phenomenon is the error classifications together with the situation awareness (SA) theories, where the findings are interlinked and hard to separate. The SA framework presents a descriptive definition of how the sub-areas are connected to each other. The error categorization, on the other hand, investigate how the prevention methods can be used for the different categorizations. The theory presented that errors caused by humans mostly are linked to personnel abilities or knowledge. Hence, the areas focusing on competence, both during the initialization of novices and throughout their careers became two important factors. When comparing the implementation of individual abilities and knowledge in this study to other published literature, the orientation of this implementation was to use the existing information and put it into a broader context to address and minimize the gap between the theory and actions in the industry. Moreover, the theories presented the importance of correct information and transparency within the company. This was presented in relation to different areas, where the different topics presented the effects of wrongly presented information and misapplication of existing technical tools from different points of view. Since the information varied and was presented from different views, it made the information hard to address and place in a context, which aligned with the identified gap. Hence, the two factors regarding the instructions and technical tools were established. After considered all assumptions and information presented above, six different areas were selected as specific areas within ZDM. The following areas were specified to support the answer of RQ 1: • Assembly instructions • Introduction for new employees • Competence of the employees • Technical assistance tools • Supplier quality • Internal quality assurance

Research question 2 – which of the specified problem areas can be identified to have the most effect of the goal of zero defects? After the problem areas were found, the work continued to identify which areas have the most effect when trying to reach a goal of zero defects. From the literature search it was stated that several different areas contributed to ZDM and they were also strengthened by the case study. At the focal company it was not seen immediately which areas that were most important, but after the interviews, polls and surveys together with

Discussion and Conclusion several discussions in the project group, it became more obvious. This was also supported by the findings from the literature in order to ensure the generalizability and the validity of the statements. Hence, to identify the different fields and to analyze their importance, a closer analysis of the findings comparing the areas against each other was needed, i.e. the disruption poll and documentation of observation data. By looking at the result from the disruption poll it could be stated that the three top areas with the highest recorded disruptions were: incorrect assembly instructions, errors caused by operators and internal quality issues. The ranking from the first poll resulted in the order of assembly instructions on a shared top ranking with the competence of the employees, which was followed by internal quality assurance. Further, by analyzing the documentation of the observation data, it could be stated that the highest recorded disruption was due to defected parts from the earlier stage, which was connected to internal quality assurance. It was both connected to internal controls, which fall under internal quality assurance, and to unclear instructions. Secondly highest observed area was the supplier quality, but due to project delimitations this area was excluded from the case. Instead, the area of assembly instructions was considered as the secondly highest data. The main problem in the assembly instructions was that they were incorrect or unclear, which was assumed to be linked to the design of the assembly instructions and to the competence of the employees. Further, this was also linked to the introduction of new employees. Supplementary, the area technical assistance tools got the lowest recorded output and was mainly recorded on operations conducted in earlier stages and was therefore overlooked in this study. Hence, the ranking of the output was internal quality assurance, followed by assembly instructions, the competence of the employees and the introduction of new employees. Thus, by comparing the first and the second data, it could be seen that the disruption poll generated the opposite ranking order to the output from the observation data. The result of a ranked list based on these two measurements of the factors were inconclusive due to deceptive and disagreeing data. Another aspect to consider while comparing the data collection is the difference in sampling methods used. The sampling of the observation data was compiled from logged disruptions over a longer period and was based on a significantly reduced documentation compared to the disruptive poll. This due to the different mindset regarding when to log the disruptions in the real system compared to the time-limited disruption poll, which was handed out during a few weeks. Hence, the ranking of the areas was ignored and instead presented as four equally important factors, since they were interconnected and affecting one another.

Discussion and Conclusion

Thus, out of the six areas found in the theory, four areas were identified to have the most effect towards the goal of zero defects. The following identified areas support the answer of RQ 2: • Assembly instructions • Introduction for new employees • Competence of the employees • Internal quality assurance

Research question 3 – how can the specified problem areas be supported by the suggested improvements? From research question 2, development was made within the specified areas, and suggestions for improvements will be presented in this section. Assembly instructions are included in all manufacturing work and are a vital part of the production. The operators need to be provided with correct and accurate instructions to do things right. Instruction should be detailed, but not contain too much information. It is a problematic equation to design it in a way that suits everyone and can be implemented by every operator. Still, suggestions for improvements were found, listed again below: • Clear guidelines with relevant details, i.e. dimensions and pictures connected to the drawing • Pictures of how to assemble critical steps • A picture showing the result after the product is assembled correctly and in its correct environment • A BOM-list structured in the way the product should be assembled • Verification after making all steps Clear guidelines mean that the instructions should contain all information needed, and it should be written understandable. The operators must be included in the design of the instructions to be able to create instructions suited for the purpose. Pictures should be added for critical moments to make it easier to realize how it is supposed to be assembled. Together with this, a BOM-list structured after how to assemble the product and verification after finalizing the steps should also be included. The verification part may not necessarily be after every single step but could for example be done after producing the first and the last part in an order to ensure that nothing was missed before the order leaves the assembly. By taking these actions about the assembly instructions, the goal was to decrease faults made internally and to prevent the operators from doing things wrong when they intend to do right. Another aspect considered was to implement an FMEA in the start-up phase of a new product in the production. It could be used to detect problems or uncertainties in the instructions at an early stage and correct them. This could prevent unclear instructions from reaching the operators and instead they could be revised and modified beforehand. Further, the problem area called introduction for new employees was found as one critical field in the work towards zero defects. In the study, this area was also linked to the problem area called competence of the employees since both fields had several connections between each other. One suggestion was to implement a training bench. 44

Discussion and Conclusion

The bench would be used by new employees for practicing in assembling a test product similar to the products that will be produced later. This would provide the new employee with a practice session free from stress, where they would be able to learn at their own pace without stressors or time constraints. Another suggestion of improvements connected both to the introduction, but especially to the competence, was to ensure the education of necessary skills among the workers. This could be done by implementing educations at regular intervals to ensure that the competence of the employees is up to date and to increase the confidence among the personnel. Moreover, internal quality assurance was identified as a key factor when striving for zero defects. The suggestion provided within this area was to complement with extra controls made by the operators. By inserting additional controls, faults made in previous steps could be detected and repaired. It would also enable learning from mistakes if the operators provided the group with information about the discovered mistakes and thus be prevented from happening again. This can be connected to the ZDM elements, detection and repair described in Figure 1, which are factors supporting the goal towards zero defects. How to add extra controls differentiates between different companies, but a suggestion discussed was to add a first and a last part control. When a new order starts, the operators put some extra time after assembling their part of the product to check if every step is completed correctly. The same procedure is then repeated after assembling the last product of the order. Another proposal was to control the steps made in previous stages and ensure that the product is faultless. Except from the obvious effect of discovering eventual faults made, it also gives the operators time to assure their assembling process and detect faults or mistakes early. From a sustainable point of view, all these suggestions of improvements would have a positive effect. If the production of defected items decreases, the claims and rework will also decrease which in turn means less impact at the environment and result in a more sustainable production.

5.4 Conclusions To accomplish a zero defect manufacturing (ZDM) with no claims from customers is a tough strategy as long as the production is manually driven. Still, it can be an endeavor worth having and it is always desirable to strive towards high goals. The difficult part with zero defects in a manually driven production is that no person is faultless, and mistakes will occur. Therefore, every instruction and every part contributing to the process should be designed in the best possible way to enable the prevention of faults and mistakes. Several aspects have been enlightened and discussed through this thesis with support both from literature as well as input from the focal company. To be able to cover the gap between the literature and the way ZDM is managed at a company, the study combined a literature search in several different fields with data collection and information from a company. This provided the study with relevant knowledge and enabled the project to answer the research questions.

Discussion and Conclusion

At the focal company, some suggestions for improvements were presented to increase their possibility of reaching ZDM. Specific fields were introduced and analyzed into what extent they contributed to the goal and purpose of the project, i.e. to find suggestions towards zero defects. It is of great importance to consider that the solutions may differ between companies, but this project can be supportive when making decisions and implementing ZDM. The conclusions from this project is to put the main focus on the following areas: • Assembly instructions • Introduction for new employees • Competence of the employees • Internal quality assurance By knowing this, companies can arrange their assets and structure the work in the best possible way. Further research in this area, based on the findings, is to continue the work to decrease the gap between literature and how it is applied at the companies. This regards especially the fields supplier quality and technical assistance tools since they were excluded in the project. The choice to exclude them was because of limitations of the project, and not because they were classified as unimportant in the strive for zero defects. Further research could therefore be done within these fields. Also, to implement the suggested improvements and evaluate the results would have been of great interest and can therefore be done through further research.

References

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Appendices

7 Appendices

7.1 Appendix 1 – Disruption Poll and Result

Appendices

Störningar i Cell grön 30 25 25

20 14 15 11 11 12 10 10 4 4 5 3 3

LPS Verktyg Slarv/missOkunskap Underlag Operatörsfel Materialbrist Testutrustning OtydligaFelaktiga underlag underlagMaskin/utrustning Materialfel (kvalitet) Testsekvens (Delta)

Fel från leverantör (extern) Akut förebyggande insats LL Fel från föregående led (intern)

Rejekt (produkt hamnar på rejektbänk) Orsakar stopp i lina/cell (hela linan/cellen…

Störningar i Lina 5 38 40 36 35 30 24 25 19 20 15 11 11 12 10 7 8 4 5 1 0

LPS Verktyg Slarv/missOkunskap Underlag Operatörsfel Materialbrist Testutrustning OtydligaFelaktiga underlag underlagMaskin/utrustning Materialfel (kvalitet) Testsekvens (Delta)

Fel från leverantör (extern) Rejekt (produkt hamnar på… Orsakar stopp i lina/cell (hela… Akut förebyggande insats LL Fel från föregående led (intern)

Appendices

7.2 Appendix 2 – Instruction Failure Poll

Appendices

7.3 Appendix 3 – Survey Assembly Instruction

Appendices

7.4 Appendix 4 – Observation Data

Appendices

7.5 Appendix 5 – Claim Data

Appendices

7.6 Appendix 6 – Competence Assessment

Appendices

7.7 Appendix 7 – Fishbone Diagram

Appendices

7.8 Appendix 8 – 5 Why Analysis

Appendices

7.9 Appendix 9 – FMEA Form

Appendices