Quality assurance in low-volume assembly line at Scania

Erik Aasa Kitiphum Noosalung

Mechanical Engineering, master's level 2020

Luleå University of Technology Department of Engineering Sciences and Mathematics E7012T

MASTER OF SCIENCE MECHANICAL ENGINEERING, PRODUCTION

Quality assurance in low-volume assembly line at Scania

Erik Aasa Kitiphum Noosalung

Division of Product and Production Development Department of Engineering Sciences and Mathematics January 20, 2020 Acknowledgement

During these months we have been working with this master thesis, corresponding to 30 credits, which is our final project. First and foremost in order to perform this thesis, we would like to express our gratitude towards Scania CV AB and the initiator of the project Christer Wilhelmsson for the opportunity.

Secondly, we have been supported by two supervisors during this period; Linda Br¨ann¨asKus´en(Scania) and Jesper Sundqvist (LTU). Thank you for all your help, by answering our questions, supported us and pro- vided guidance on how to move on during the entire project. In additional, a special thanks to the DTTGP department of Product Introduction and E-mobility Projects, everyone we met during our study visits for your collaboration, effort, time, inspiration and also for the period enriched with experience.

Last but not least, we would like to thank our families and friends for the support, belief and encour- agement throughout all these years. Thank you all, we really do appreciate it!

...... Erik Aasa, S¨odert¨alje January 20, 2020

...... Kitiphum Noosalung, S¨odert¨alje January 20, 2020 Abstract

Scania are now going through a transformation process from being a supplier of trucks, busses and engines to a supplier of complete and sustainable transport solutions. Scania’s transmission assembly department in S¨odert¨aljeis facing a variation of changing challenges linked to the powertrain and customer of tomorrow. Some of the challenges is related to assuring quality on low-volume electrified and hybridised products. In this thesis quality assurance of a low-volume assembly line at transmission’s department has been investigated.

The aims for the thesis project are to evaluate today’s methods, equipment and process descriptions for how quality assurance are handled and how it can be implemented in a low-volume assembly line. The aim is to investigate what kind of quality assurance methods exist within Scania but also externally. The purpose is to give suggestions for Scania on which quality assurance methods are suitable for Scania’s low-volume assembly line. Today the current level of quality assurance in a low-volume line is considerable low and the production have many processes between start and delivery. The production start with an order initiation which prints out a list of assembly order and included parts. The processes are manually handled by one operator from the beginning to the end and the work includes assembly, material picking and quality control. Due to limitations and lack of equipment, the assembler have a lot of responsibility. The processes are also lacking of traceability and have a high risk for allowing deviations to be build in the product. The current processes leads to increased risks of rework, longer lead time and lower quality.

The thesis project started with a literature study with the focus on quality, quality assurance and lean production. A current state analysis was done to gain knowledge of the processes and to identify problems within the current state. Identified problems were through observations, interviews and analysis of PFMEA document. The problems were risks that could affect quality of the product, and it was then categorized into three major risk groups; pick, place and tools. To seek which equipment there are to handle these risks, how other companies and departments are working with quality assurance, internal and external study visits were carried out. Internally within Scania; Smart Factory Lab, Engine Assembly and Chassis Assembly. Externally; Volvo Group Trucks Operations K¨opingand Volvo CE Arvika. The results of the visits were evaluated to create a solution to make a suitable suggestion in term of cost, quality and flexibility for Scania.

The thesis project resulted in a study that showcase what quality assurance methods and equipment ex- isted on the market and what other companies are using to quality assure. The result is that for similar production, the companies are using rather similar methods and equipment. Equipment to handle risks, deviations involving picking materials and assembly. For Scania’s low-volume production a solution and a recommendation of equipment was given. To handle the existing deviations and for upcoming similar low- volume production. Quality assurance equipment and methods are expensive but is considered necessary, a necessary cost and necessary waste. Scania is recommended to invest in short and long term solutions where the short term is to improve the current state. In a short term to secure the picking operations with easier solutions of dividing parts into boxes or trays on the cart during transportation from shelves. Installing pick to light connected to nutrunners for critical parts and further develop the digitalized checklist for improv- ing visualization. In longer term, Scania should invest in quality assurance equipment for low-volume lines. Prioritize and invest in creating infrastructure for connection between equipment and tools to secure critical parts in early stages of the project. Finally, create a communication between Scania’s internal plants in order to further improve and share the quality assurance knowledge.

Keywords: quality, quality assurance, wastes, deviations, low-volume, assembly Sammanfattning

Scania genomg˚arnu en transformation fr˚anatt vara en leverant¨orav lastbilar, bussar och motorer till en lever- ant¨orav kompletta och h˚allbaratransportl¨osningar.Scanias transmissionsmontering i S¨odert¨alje st˚arinf¨or flera utmannande f¨or¨andringarkopplade mot framtidens drivlina och kunder. Utmaningar att s¨akrakvaliten av l˚agvolyms produkter, som ¨arprodukttyper av elektrifiering och hybridisering. Detta examensarbete har genomf¨orten unders¨okning av kvalitetss¨akringhos transmissionsmonteringens l˚agvolyms monteringsfl¨oden.

Projektets m˚al¨aratt utv¨arderahur dagens metoder, utrustningar och processbeskrivningar f¨orkvalitetss¨akring hanteras och hur det kan till¨ampasi en l˚agvolyms monteringsfl¨oden.Syftet ¨aratt unders¨oka vilka kvalitetss¨akrings metoder som finns inom Scania och extern p˚amarknaden. D¨arefterta fram f¨orslagp˚ametoder och utrust- ningar som ¨arl¨ampligaf¨orScanias l˚agvolyms monteringsfl¨oden.Dagens niv˚aav kvalitetss¨akringsi l˚agvolyms monteringsfl¨odenanses vara l˚agoch produktionen inneh˚allerm˚angaprocesser fr˚anb¨orjantill slut. Pro- duktionen b¨orjarmed en initiering av order som skriver ut en monteringslista med inneh˚allandeartiklar. Processerna hanteras manuellt av en mont¨orfr˚anstart till slut och arbetet innefattar montering, materi- alplock och kvalitetskontroll. P˚agrund av begr¨ansningaroch brist p˚autrustningar har mont¨orenv¨aldigt stort ansvar. Processerna saknar ¨aven sp˚arbarhetoch har en h¨ogrisk f¨oratt till˚ataavvikelser att byggas i produkten. Nuvarande processerna leder till ¨okade risker f¨oromarbetning, ledtid och minskad kvalitet.

Examensarbetet inleddes med en litteraturstudie med fokus p˚akvalitet, kvalitetss¨akringoch lean produk- tion. En nul¨agesanalysgenomf¨ordesf¨orf˚akunskaper om processerna och identifiera problem inom nul¨aget. Problemen identifierades genom observationer, intervju och analysering av PFMEA dokument. Identifierade problemen var risker som kunde p˚averka kvalitet p˚aprodukten, riskerna kategoriserades d¨areftertill tre hu- vudrisker; plock, montering och verktyg. F¨oratt s¨oka vilka utrustningar som kan hantera dessa risker, hur andra f¨oretagoch avdelningar arbetar med kvalitetss¨akringgenomf¨ordesinterna och externa studiebes¨ok.In- terna inom Scania; Smart Factory Lab, Motormontering och Chassimontering. Externa; Volvo Group Trucks Operations K¨opingoch Volvo CE Arvika. Resultaten av studiebes¨oken utv¨arderadestill att skapa en l¨osning f¨oratt g¨oraen l¨ampligf¨orslag f¨orScania med avseende p˚akostnad, kvalitet och flexibilitet.

Examensarbetet resulterade i en studie som p˚avisarvilka kvalitetss¨akringsmetoder och utrustningar exis- terar p˚amarknaden och vad andra f¨oretaganv¨ander.Resultaten visar att f¨orliknande produktion, anv¨ander sig f¨oretagenlikadana metoder och utrustningar. Utrustningar som hanterar risker, avikelser som ber¨or materialplockning och montering. F¨orScanias l˚agvolymsproduktion har en l¨osningoch rekommendation av utrustningar presenteras. F¨oratt hantera nuvarande avvikelser och framtidens likande l˚agvolymsproduktion. Kvalitetss¨akringsutrustning och metoder ¨ardyra men anses vara n¨odv¨andigt,en n¨odv¨andigtkostnad och n¨odv¨andigtsl¨oseri. Scania rekommenderas att satsa p˚akort- och l˚angsiktigal¨osningard¨arde kortsiktiga ¨ar att f¨orb¨attranul¨aget. P˚akortsikt att s¨akra plocknings operationer med enkla l¨osningargenom att separ- era artiklar in till l˚adorp˚atransportvagnen vid transportion fr˚anhyllorna. Installera pick to light kopplad till skruvdragare f¨orkristiska artiklar och vidare utveckla digitaliserade checklistor f¨orb¨attrevisualisering. P˚al˚angsiktb¨orScania satsa p˚akvalitetss¨akringutrustningar f¨orl˚agvolymsmonteringsfl¨oden.Prioritera och investera i att skapa en infrastruktur f¨oruppkopplade utrustningar till att s¨akrakritiska artiklar tidigt i pro- jektstadie. Avslutningsvis skapa en kommunikation mellan Scanias interna fabriker f¨oratt vidare f¨orb¨attra och dela med sig kunskaper om kvalitetss¨akring.

Nyckelord: kvalitet, kvalitetss¨akring,sl¨oserier, avvikelser, l˚agvolym, montering List of Figures

1 Scania House, Main principles. Source: Scania Inline (2019)...... 2 2 TPS House. Source: Liker (2009)...... 7 3 Scania Production System. Source: Scania Inline (2019)...... 8 4 Project method processes ...... 14 5 Example of low-volume layout...... 19 6 Pareto diagram of current quality risks in the studied work station ...... 21 7 Pareto diagram of remaining quality risks after measures in the studied work station . . . . . 21 8 Bar chart of mean RPN before and after measures is taken against most critical risks . . . . . 22

List of Tables

1 Cost estimation of solutions ...... 31 2 Example of quality assurance cost for a low-volume assembly ...... 32 3 Cost estimation of low-volume solution, current state example ...... 33 4 Equipment and its risk category ...... 34 List of Abbreviation

DFMEA Design Failure Mode and Effects Analysis. DTV Daily Torque Verification.

FMEA Failure Mode and Effects Analysis.

LTU Lule˚aUniversity of Technology.

P2L Pick To Light. P2V Pick To Voice.

PBT Pick By Tablet. PBV Pick By Vision. PFMEA Process Failure Mode and Effects Analysis. PQMO Project Quality Manager Operations.

RPN Risk Priority Number.

SOP Start Of Production. SPS Scania Production System.

TPS Toyota Production System.

VCE Volvo Construction Equipment. VGTO Volvo Group Trucks Operations.

WIP Work In Progress. Contents

1 Introduction 1 1.1 Scania Introduction ...... 1 1.2 Background For The Project ...... 1 1.3 Objectives ...... 2 1.4 Delimitations ...... 3

2 Theoretical Framework 4 2.1 Quality ...... 4 2.1.1 Quality Dimensions ...... 4 2.2 Quality Assurance ...... 5 2.2.1 Jidoka ...... 5 2.2.2 Poka-Yoke ...... 6 2.3 Lean Production ...... 6 2.3.1 Scania Production System ...... 7 2.3.2 Principles ...... 10 2.3.3 Sub Principles ...... 10 2.3.4 Priorities ...... 11 2.4 Assembly Layout ...... 11 2.4.1 Functional Layout ...... 12 2.4.2 Line Layout ...... 12 2.4.3 Fixed Layout ...... 12 2.4.4 Combination Layout ...... 12

3 Methodology 13 3.1 Research Purpose ...... 13 3.2 Time Plan ...... 13 3.3 Research Approach ...... 13 3.4 Research Methods ...... 14 3.4.1 Qualitative Research ...... 14 3.4.2 Quantitative Research ...... 15 3.5 Benchmarking ...... 15 3.6 Data Collection ...... 15 3.7 Process Failure Mode and Effects Analysis ...... 16 3.8 Observation ...... 16 3.9 Study Visit ...... 16 3.10 Interview ...... 17 3.11 Evaluation of Alternatives ...... 17 3.12 Finalization ...... 18 3.13 Reliability ...... 18 3.14 Validity ...... 18

4 Current State 19 4.1 Assembly station layout ...... 19 4.2 Order system ...... 19 4.3 Controlled nutrunner with socket and bit selector ...... 19 4.4 Checklist ...... 20 4.5 Hydraulic Press ...... 20 4.6 Material Handling ...... 20 4.7 Material transportation cart ...... 20 4.8 Current Quality Assurance ...... 20 4.8.1 General quality risks ...... 22

5 Result and Analysis 23 5.1 Study visits ...... 23 5.1.1 Smart Factory Lab ...... 23 5.1.2 Engine Assembly ...... 25 5.1.3 Chassis Assembly ...... 26 5.1.4 Volvo Trucks Operation, K¨oping ...... 27 5.1.5 Volvo CE, Arvika ...... 28 5.1.6 Analysis Study Visits ...... 30 5.1.7 Conclusions ...... 36 5.2 Interviews ...... 37 5.2.1 Respondent 1: Quality manager, Chassis Assembly department ...... 37 5.2.2 Respondent 2: Process Engineer, Engine assembly department ...... 38 5.2.3 Respondent 3: Production engineer, Volvo Group Trucks Operation, K¨oping . . . . . 38 5.2.4 Respondent 4, Production engineer, transmission assembly ...... 39 5.2.5 Analysis of Interviews ...... 40 5.2.6 Conclusions ...... 41

6 Discussion 42 6.1 Project Execution ...... 42 6.2 Validity and Reliability ...... 42 6.3 Recommendations ...... 43 6.3.1 Short term ...... 43 6.3.2 Long term ...... 44

7 Conclusion 45 7.1 Research Questions ...... 45 7.2 Target fulfillment ...... 45

A Gantt Chart i

B Interview Guideline ii 1 Introduction

This section includes the introduction of Scania, background for the project, objectives and delimitations of the master thesis.

1.1 Scania Introduction Scania AB was formed in 1911, at the time named Scania-Vabis AB as a result of a merger between S¨odert¨alje based Vabis and Malm¨obased Maskinfabriks aktiebolaget Scania. Scania has under a long time been a man- ufacturer of commercial vehicles such as heavy trucks and buses but also a manufacturer of engines. Today the company has approximately 52 000 employee all around the world and are offering sales and services in more than 100 countries (Scania 2019a).

Scania is a world leading provider of transport solutions and to keep the position of the leading provider, together with their partners and customers, they are driving the shift towards a sustainable transport system as they are ongoing transformation into a supplier of a complete and sustainable transport solutions (ibid.).

1.2 Background For The Project Scania are now going through a transformation process from being a supplier of trucks, buses and engines to a supplier of a complete and sustainable solution. Scania’s transmission assembly department in S¨odert¨aljeis facing a variation of changing challenges linked to powertrain of tomorrow and customer. The transmission assembly department produces both gearboxes and axles to Scania’s chassis assembly department in Zwolle, Angers, S¨odert¨aljeand also MAN’s chassis departments.

Scania’s aim is to drive the transition to a sustainable transport solution and create a world of mobility that benefits the company, society and environment. A step into this journey is to increase hybridization and electrification. The development is growing rapidly and Scania demand high standard on the quality of the new technique.

Scania’s success is based on their core values, Customer first, Respect for the individual, Elimination of waste, Determination, Team spirit and Integrity, these core values are the foundation of the Scania House which symbolises Scania’s management system (ibid.). The core values are supported by the Main principles as shown in Figure 1.

1 Figure 1: Scania House, Main principles. Source: Scania Inline (2019).

The main principles of the Scania House, Demand driven output, Normal situation, Right from me and Continuous improvements, together form a continuing work process and mindset, where the goal is to add customer value and eliminate waste.

Today, the manufacturing of the majority of gearboxes are in the Main line, this Main line consist of so called high-volume process. The Main line is producing high quantity and is highly equipped with the right tools to ensure quality. Scania also has low-volume lines for manufacturing of gearboxes such as, electric, hybrid and development state gearboxes. The production of these are limited and therefore investment in pro- cessess are lower. Scania demand quality and believes it is possible to obtain high quality for the low-volume processes. This lead to consideration of quality assurance in terms of quality, cost and flexibility. Ensuring quality is very important for Scania because of for example, the core value Customer first and main principle Right from me.

1.3 Objectives The aims for the thesis project are to evaluate today’s methods, equipment and process descriptions for how quality assurance is handled and how it can be implemented in a low-volume assembly line. The aim is therefore to investigate what kind of quality assurance methods exist within Scania but also externally. The purpose is therefore to make suggestions for Scania which quality assurance methods are suitable for Scania’s low-volume assembly line. These processes are different and excluded from Scania’s main line for gearbox assembly and has a very long takt time, thereby termed low-volume processes. To fulfill the objectives and aim the following research questions will be answered: • Which quality assurance methods and equipment exist on the market? • Which quality assurance methods and equipment are suitable for Scania’s low-volume processes in terms of cost, quality and flexibility?

2 – Cost definition: cost of the equipment and cost per risk – Quality definition: How well the equipment secure free from fault, equipment’s reliability – Flexibility definition: Equipment ability to adapt for product changes. • How can the suggested methods and equipment be implemented in Scania’s low-volume processes?

1.4 Delimitations To ensure that the master thesis stayed within the scope and corresponds to 30 credits, some delimitations were made: • The machines, tools and measuring equipment are assumed to be correctly set and calibrated. • Assembler are expected to be fully qualified and possess enough experience. Therefore will preparatory education not be taken into consideration. • Lack of free space will not be taken into consideration. • Materials delivered from supplier are assumed to be faultless.

By these delimitations the subject are narrowed down for the project and put the focus on the key aspects.

3 2 Theoretical Framework

This chapter presents the theoretical framework used in this thesis project. The sources for the literature reviews have been both books and scientific articles.

2.1 Quality There are many aspects of quality in the business context, but the primary thing is that the business produces something, it could be a product of physical goods or some services. How well these products are produced could define quality. Product quality perception comes from your design specifications and the manufacturing standards achieved. Service quality perception comes from service process design and standard of delivery. The effects of quality are experienced by the customer (Sondalini 2019). But quality is a somewhat subjec- tive attribute and may vary and be understood differently by different people. Some well known definitions are ”fitness to use” by Joseph Juran, ”conformance to requirements” by Philip Crosby and ”quality should be aimed at the needs of the customer, present and future” by Edwards Deming. According to Bergman and Klefsj¨o(2012) the first two definitions of quality got a producer perspective which does not benefit the customer. The later one is more customer oriented and show the importance of customers focus in mind. Bergman and Klefsj¨o(ibid.) have define their own interpretation of quality,

”Quality of a product is its ability to satisfy and preferably surpass the customers needs and expectations.”

The definition implies that it is not enough to just fulfill the customer needs but should also strive for exceeding their expectation. The customer should be surprised and delighted of the solutions. By this you could create a positive relationship with the customers which could lead to other benefits.

2.1.1 Quality Dimensions A product or a service has many attributes which are perceived by its customers and thereby affects their perception of the products and services. To be able to fulfill and satisfy the needs of the customers related to the attributes, the customers must first be defined. As there are different interpretations of ”quality”, there is the same for the concept of ”customer”. According to Bergman and Klefsj¨o(ibid.) customers could be people or organizations that exist within or outside of our own organization. Two other definitions are ”people or group that has the interest of the organization’s performance or success” by ISO 9000:2005 and ”anyone who is affected by the product or by the process used to produce the product” by Joseph Juran. When the customers are defined the upcoming work is to improve these attributes and these attributes out of quality aspect are called quality dimensions. Some of the quality dimensions for a product are as following: • Operation security, is about how frequently deviation occurs and how serious it is. • Performance of significance for customers, such as speed, effect and life span. • Maintainability, how easy it is to detect, locate and fix errors.

• Environmentally friendly, the product impact on environment, such as exhaust of gases and recover- ability, how these aspect are taken in consideration in the production. • Appearance, aesthetic parameters such design and colors. • Free from fault, as the product does not got any defects at the purchased moment.

• Security, the product does not harm the person or other property. • Durability, the product can be used, stored and transported without deterioration.

4 For service are some of the quality dimensions as following: • Reliability, the service’s punctuality, precision and delivering that was promised. • Credibility, the trust and faith in the supplier. • Availability, how easy it is to contact the supplier. This includes how open mindset and possibility to contact supplier by phone or other communication ways. • Communication, the ability to communicate in an easy and clear way for the customer, so it is com- prehensible for the customer. • Service, the will to serve and help the customer. • Courtesy, supplier’s behavior of civility, thoughtfulness and kindness. • Empathy, the ability to empathize with the customer in different situations. • Environment, the physical environment when the service is provided, location’s and equipment’s ap- pearance. These quality dimensions are quite different between the product and service. The difference is that these dimensions of quality are experienced differently. For example the quality of a product is reflected after the purchasement of the product, when the production and processes are done which means the quality could be tested before deliver to the customer. For services it is a event of activities, the customer will not be provides of something physical which means the quality can not be tested prior to the purchase. Service is special, it is consumed as the same time as it is created and the customer is involved in the process of the quality. This situation called ”the moment of truth”, when the customer is evaluating everything as a whole. Therefore the quality of a service should be seen as a relationship between service, supplier and also the customer (Bergman and Klefsj¨o2012).

2.2 Quality Assurance 2.2.1 Jidoka According to Petersson et al. (2015), Jidoka is one of the two main principles of the Toyota Production System (TPS). The meaning of the concept Jidoka is to secure quality in the products and services by taking actions in order to make it easier to do right the first time and to stop the process to fix errors - Jidoka can thus be divided into two branches: • Built-in quality • Stop the process to fix errors The first branch, Build-in quality, infers that the quality of the products and services is secured by securing quality in the processes. Key success factors for built-quality, according to Petersson et al. (ibid.), is: • Customer and customer needs are explicitly defined • Modus operandi is designed to make it easy to do right • Operators use standardized work • Operators possess the qualifications required The second branch of the principle Jidoka, Stop the process to fix errors is, according to Petersson et al. (ibid.), to stop the processes involved, or at least react and take action, when a problem occurs and deal with the problem at once to minimize value added to products or services containing errors.

5 2.2.2 Poka-Yoke The Poka-Yoke concept according to B˘alanand Jant˘a(2019) was developed by Japanese engineer Shigeo Shingo in the 1960’s as a way to prevent errors and defects in the production processes. In Japanese the meaning of the term Poka-Yoke is: poka - avoidance, yoke - error. A poka-yoke is a device designed to identify errors in the process so no failures will be passed on to the next work station. The goal, according to Liker (2009) and Petersson et al. (2015), is to make it almost impossible for the assembly workers to perform activities in the wrong way and it is thus part of a way to achieve the Jidoka branch built-in quality. B˘alanand Jant˘a(2019) suggests that a poka-yoke system contains four main elements: read - algorithm - information - lock. • read - the system identifies the action that is intended to be checked for errors • algorithm - the decision maker that identifies if there is an error or not

• information - the component that the system uses to respond with information if the action is OK or NOK. • lock - if the system has detected an error, a non-conformity, the lock component of the system removes the possibility of continuing the work operation any further

A fifth additional element of the system is the disturbing factors - that interfere with and can disturb the proper functioning of, the poka-yoke system. B˘alanand Jant˘a(ibid.) also argues that there is three levels of Poka-Yoke devices: • interdiction / forbiddingness - that makes it impossible for errors to occur. • control - measures and informs but does not forbid

• alert - alerts the operator when non-conformances appear

2.3 Lean Production Lean production or just Lean is a concept, a strategy and a production philosophy that is associated with Toyota, an automobile manufacturer, on how they created and implemented their philosophy. Even though the Lean concept is often associated with Toyota and TPS, the concept was first introduced in the 20st cen- tury. According p˚aPetersson et al. (2015) the whole thing started when people such as Benjamin Franklin, Frank Gilbreth and Frederick Winslow Taylor inspired Henry Ford to create an efficiency production system. Ford had created what so called a production flow and started the thinking of what would be today called Lean, at least concerning the material flow aspect not concerning the people and the organization. This would later be taken upon by Toyota.

The Toyota Production System is focused on customer demand and to reduce cost through elimination of waste, but the key is within the central piece of the organization, the people (Liker 2009). According to Liker (ibid.) the TPS is built upon 14 principles which later are categorized into a 4P-model. The 4P-model includes Problem Solving, Process, Partners and Philosophy. These are the key of Lean and TPS, under each category there are tools, methods and mindset described as guidelines for the organization to improve their production and services. How these are used and implemented for respective company are often presented in form a house or temple similar to the Toyota’s TPS House, as seen in Figure 2.

6 Figure 2: TPS House. Source: Liker (2009).

Petersson et al. (2015) also mention that TPS cannot be copied by other organization, not directly and without adaptation. Other organization have to adapt the principles and methods to their respective situ- ation as Lean is dependent on each company’s ability to ensure the Lean culture, a culture of continuous improvement and that the principles and methods are followed. Thus the reason a long term solution is highlighted as the most crucial factor for Lean (Petersson et al. 2015; Modig and Ahlstr¨om2017;˚ Liker 2009).

According to Modig and Ahlstr¨om(2017)˚ Lean is highly focused on the customer and the goal is to elimi- nate all that does not add value for the customer which in turn would increase the value and profit for the company. But also Petersson et al. (2015) state that reducing the resource is not always better, Lean is about being efficient, by that means using the right resources and the right amount of resources in the most effective way.

2.3.1 Scania Production System Like many other organization Scania is working with Lean and they are very successful in it. Scania’s organization is built upon a production system, a system that is called Scania Production System (SPS). This is the core of the company and their philosophy on how they are working and strive for continuous improvement. SPS is in turn built upon TPS but with adaptation to Scania’s values and foundations. The house of SPS is as following, Figure 3.

7 Figure 3: Scania Production System. Source: Scania Inline (2019).

The house’s foundation consist of three of the core values, Customer first, Respect for the individual and Elimination of waste. In the past recent years Scania has added additionally three more core values, Integrity, Determination and Team spirit. These are described as the key of Scania’s success: • Customer first means that the customer’s requirements and expectation should permeate the organi- zation and these should be exceeded, as Bergman and Klefsj¨o(2012) mentioned. Customer by this is not just the end customer but define as the upcoming processes all the way to the end customer. • Respect for the individual means that each individual are being considerate of, the work place is secure, treat others the way we want to be treated, the communication is straight forward and open. Capture the knowledge, experience and ambition of each individual to continuously improve and also information of demands and expectations on each individuals are clear. • Integrity is related to social responsibility and always strive to do the right things in the right way. Scania act in accordance with the culture, core values and principles. Follow all legal and compliance standards. Having trust and thereby builds relationships with customers, business partners and society at large, making it one of the important assets. To always keep promises and are accountable for work. • Determination, to be dedicated all the way and motivated to reach beyond the next level. Take pride in meeting challenges with innovative solutions, and always learn from experiences. Being aware of details, while fully understanding the bigger picture, generates value for the organization and the customers. • Team spirit is about joining forces and work openly across borders, towards a common goal to be number one in the industry. Look at differences and diversity as opportunities, and challenge each other to become better. A shared sense of direction brings collective strength and a group belonging.

8 • Elimination of waste, with a strong focus on continuous improvements throughout the entire organisa- tion, Scania ensure safe and high quality output in all areas. Deviations from targets and standards help Scania to identify and eliminate waste. In everything, internally as well as externally, Scania strive to optimise the flow and resource efficiency while minimising the environmental footprint. The last mentioned value Elimination of waste, it is also to always question and challenge the organization in all that does not add value to the customers. Scania has categorize the wastes in eight different wastes, this resembles the 7+1 wastes mentioned by Liker (2009).

• Defects, waste from a product or service that fails to meet the customer expectations. Result in either reworking or scrapping the product. The results are wasteful as they are adding additional cost to the operations without adding any value to the customer. • Overproduction, waste from making more products than customers demand. Manufacturing a product or an element of the product before it is being asked for or required. It may be tempting to produce as many products as possible when there is idle worker or equipment time. Result in preventing smooth flow of work, higher storage costs and excessive lead-time. In an office environment, overproduction could be making extra copies, creating reports no one reads, providing more information than needed, and providing a service before the customer is ready. • Waiting, time spent waiting for the next process step to occur. Waiting time is often caused by unevenness in the production stations and can result in excess inventory and overproduction. This could be people waiting on material or equipment and idle equipment. In the office, waiting waste can include waiting for others to respond to an email, having files waiting for review, and ineffective meetings. • Transportation, wasted time, resources, and cost when unnecessary moving products and materials. In the office, workers who often collaborate with each other should be close together. In the production, materials necessary for production should be easily accessible at the production location and double or triple handling of materials should be avoided. Waste in transportation includes movement of people, tools, inventory, equipment, or products further than necessary. Excessive movement of materials could damage and lead to defects of the products. Additionally, excessive movement of people and equipment could results in unnecessary work, wear and tear, and also exhaustion. • Inventory, wastes resulting from excess products and materials that are not processed. Having more inventory than necessary to sustain a steady flow of work could lead to problems, such as product defects or damaged materials, greater lead time in the processes and problems being hidden away in the inventory. Excess inventory could be caused by overpurchasing or producing more products than the customer needs. Excess inventory prevents detecting production related problems since defects have time to accumulate before it is discovered. As a result, it could lead to other wastes such more work will be needed to correct the defects.

• Motion, focused on peoples, wasted time and effort related to unnecessary movements. The waste in motion includes any unnecessary movement of people, equipment, or machinery. This includes walking, lifting, reaching, bending, stretching, and moving. Tasks that require excessive motion should be redesigned to enhance the work of personnel and increase the health and safety levels. Manufacturing motion wastes are such as repetitive movements that do not add value to the customer, reaching for materials, walking to get a tool or materials, and readjusting a component after it has been installed.

• Extra processing, wastes related to more work or higher quality than is required. Extra-processing refers to doing more work, adding more components, or having more steps in a product or service than what is required by the customer. In production this could include using a higher precision equipment

9 than necessary, using components with capacities beyond what is required, running more analysis than needed, and having more functionalities in a product than needed.

• Unused talent, skill or talent the plus one waste according to Liker (2009) and Petersson et al. (2015). The waste of human potential. Described as the waste of unused human talent and ingenuity. This waste occurs when organizations separate the role of management from employees. In some organizations, management’s responsibility is planning, organizing, controlling, and innovating the production process. The employee’s role is to simply follow orders and execute the work as planned. By not involving the worker’s knowledge and expertise, it is difficult to improve processes. This is due to the fact that the people doing the work are the ones who are most capable of identifying problems and developing solutions for the organization.

2.3.2 Principles The rest of the house consist of variation of principles that Scania is working by. It is divided into Main principles and Sub principles. The main principles of the SPS, Demand driven output, Normal situation, Right from me and Continuous improvements, together form a continuing work process and mindset, where the goal is to add customer value and eliminate waste. • Normal situation is build upon sub principles that serve as tools to fulfill this main principle. Those are Standardisation, Takt, Levelled flow, Balanced flow, Visual and Real time. These are described in section 2.3.3 Sub Principles.

• Demand driven output mean that nothing is produced without having been ordered or needed by the customer. • Right from me is exercised by not accepting faulty deliveries and making sure that everything is done correctly before it is sent forward in the process. Tools, instructions and methods provided are used to make sure it is impossible to produce defects. Right competence and quality methods, assurance for the process, and also to not be afraid to report deviations, even the tiniest deviations are crucial to fix. • Continuous improvements, all of the above form a continuing working process. Improve the processes and customer offering, all employees at Scania contribute with experiences and ideas in order to improve their work situation. This is illustrated as the roof of the SPS, three existing levels are described. First level is to handle deviations, a daily process. Second level is to improve the processes and lastly third level is to challenge the process to improve in long term.

2.3.3 Sub Principles As mentioned previously there are some sub principles that are tools to fulfil the Normal situation. That main principle is supported by following sub principles (Scania 2019b). • Standardisation means that it is not only important what is done but also how it is done. Standardising manual work means that the work is described and undertaken in exactly the same way every single time so that recurring problems can be discovered and rectified. With standardisation, Scania carry out the tasks in the same way until Scania arrive at how the work can be even better. Use the best-known established working methods. • Takt reflects the customers’ demands. A takted system monitors demand throughout the flow. Over- production is avoided and Scania produces in accordance with specific demand. By maintaining a set takt the position and situation is known. Another important benefit is that it is easier to discover deviations and unnecessary tasks.

10 • Levelled flow means that the production volumes are evened out and distribute labour-intensive units across the working day. To utilise the resources and plan the operations in an efficient way. On some occasions received many customer orders and on other far fewer. Scania’s incoming order queue and buffer of delivery-ready vehicles serve as two breakwaters at either end of the flow. This helps to even out the flow in production • Balanced flow means that as far as possible, the work is uniformly distributed between those resources that will be doing the work. It’s all about ensuring a smooth and high work-load so it can optimise the capacity and benefit from the available efficiency synergies. On an assembly line, each step is analysed along with the time it takes. This is followed by calculations to distribute the work evenly between the various positions. • Visual, In order to be able to see where Scania are in relation to the normal situation, the organization need easily accessed, simple and clear information. Here it is important that the flow patterns are simple, straightforward, visual and easy to overview. This allows to respond in real time to deviations. Different ways of visualising may also differ in their effectiveness. The most efficient visualisation is quick to see and easy to interpret. Light signals, for instance, are an example of good visualisation. Sometimes it may also be effective to utilise sound for the purpose. • Real time means both react and act here and now. All information has a limited shelf life. It is therefore important that those affected by information should receive it quickly. Real time is particularly important when it comes to finding reasons for deviations. An event that led to a deviation needs to be captured immediately. With the passage of time, the information disappears and the process of analysis becomes more difficult. Even if there is not always the possibility of analysing a deviation in real time, it is important to secure the information as far as possible, for instance via photographs. At the same time finding a short term solution so the customer is not affected. Rectify deviations in real time and also provide feedback in real time to the previous stage in the hierarchy, where the deviation actually occurred.

2.3.4 Priorities In the central of the SPS there is the shared organization priorities. The organization need to have the same priorities in order to quickly make the right decision. The priorities are as follows: • SHE stands for Safety, Health and Environment • Quality • Delivery • Cost These priorities are seen as a compulsory list. Always prioritise the safety, at the same time having high quality, deliver on time and maintain a competitive cost structure that makes Scania profitable. The order of priority only comes into play in the event of an abnormal situation or when the priorities are incompatible with one another. The safety, health and environment of the people always have the top priority. Putting quality ahead of delivery means that Scania do not deliver products that are not of perfect quality (Scania 2019b).

2.4 Assembly Layout There exist a couple of different production layouts, which are suitable for different purposes, manufacturing and organizations. This is because the layouts are dependent of and affects factors such as production volume, variations and at the time competitive situation (Larsson and T¨ornbom 2010).

11 2.4.1 Functional Layout This layout, functional layout is particularly useful where low volume of production is needed. If the products are not standardized, the functional layout is desirable, because it has higher process flexibility than other. In this type of layout, the machines are not arranged according to the sequence of operations but are arranged according to the type of the operations. For example all the lathes will be placed at one place and all the drill machines are at another place. The disadvantages are such as higher lead time and more floor space required (Bellgran and S¨afsten2005).

2.4.2 Line Layout The equipment that are required to produce the product are placed in line according to the sequence of the operations. This for example for assembly operation, different parts are divided in each operating area. This type of layout gives a good overview of the processes and material flow. It is also preferable for production of larger quantities. The drawback for line layout is that deviation or machine downtime affects the whole line. Unlike functional layout this type contributes to lower Work In Progress (WIP) and shorter lead time (ibid.).

2.4.3 Fixed Layout In the fixed layout the major component is placed in a fixed location, and the materials, tools, machinery, other supporting equipment’s are brought to the fixed station. The major component or body of the product remain in a fixed position because of reason such as, it is too heavy or too big. It could also be more economical and convenient to bring the necessary tools and equipment’s to work the place along. This type of layout is suitable for lower investment and lack of space. Limitations for the layout are also space for material handling, cost of fixtures and require skilled manpower due to more responsibility (ibid.).

2.4.4 Combination Layout Flexibility is a very important factor, nowadays a pure state of each of the above layouts is rarely found. A mix of the layouts are used according to the requirements and preference of each company. Therefore, the layouts used in the industries are a compromise of the mentioned layouts. Each layout has certain advantages and limitations, by creating a solution of their own mix, the company could obtain a more economical and flexible result suitable for respective organization (ibid.).

12 3 Methodology

In this section the methodology used in this thesis project is presented first by describing the theory and secondly how theory was implemented in the project.

3.1 Research Purpose The purpose of the research is to investigate how to improve quality assurance in assembly processes with low-volume throughput. The research done lie as a ground for concept development for quality assurance activities and process descriptions where named concepts is included.

3.2 Time Plan According to Bergman and Klefsj¨o(2012) a way to establish a time plan for new projects can be done by constructing a Gantt-chart. The Gantt chart gives a clear image of different phases of the project, activities included in the phases, deadlines of activities and time left to keep up with the projects pace. A sketch of the Gantt-chart was established before the start of the thesis project and was later refined during the first weeks. In addition to the Gantt chart, which gives an overview of the projects timeline, a detailed project description was developed in company with supervisors from Scania and Lule˚aUniversity of Technology (LTU). In the detailed description the projects scope, delimitations, purpose, expected problems, solutions to expected problems and possible further expansions of the project was described. The Gantt chart can be seen in Appendix A.

3.3 Research Approach According to Tjora (2016), research can be devided into inductive and deductive sides. An inductive approach means that by observation of a number of individual cases, assumptions of general relations can be made. Deductive approach, on the other hand, is to explain individual events based on general theory. According to Tjora (ibid.) qualitative research tends to lean towards the inductive approach with empirical investigation by gathered impressions and experiences. In this thesis project, existing assembly stations and equipment setups was about to be investigated in order to make improvements and find ways to secure quality in the dedicated assembly line, i.e. empirical investigation turned into general theory. thus the inductive approach was chosen.

13 Figure 4: Project method processes

3.4 Research Methods The methods of research contains two different sections, qualitative research and quantitative research. In this thesis project mostly qualitative research was done due to the unspecific problem scope and the measurability of the existing process. Some quantitative research was made in order to find out how to prioritize different abnormalities and risks with regards to quality.

3.4.1 Qualitative Research To gain deeper knowledge about the problem, qualitative research was made through observation, interviews and study visits. Observations were done at different assembly departments internally at Scania to get a grip on how far quality assurance equipment is used and implemented within the company, at different assembly lines that has been up and running for a longer time than the P160 in this study. Interviews are according to Tjora (2016) the most common way of collecting qualitative data. In this project, interviews were held with both internal personel but also with external companies with similar manual low volume assembly in their production.

14 3.4.2 Quantitative Research The Quantitative research is often made through collection and analysis of numbers such as costs and times or other quantifiable data. In order to find main priorities about what issues of quality that has the biggest effects on the company statistical research and analysis on occurring quality deviations both internally and externally but also on expected risks of quality deviations in the processes.

3.5 Benchmarking To further improve a company’s own processes, benchmarking is according to Bergman and Klefsj¨o(2012) a method used to find possibilities of improvements, by comparing similar processes at other companies. When benchmarking, the goal is to find the best possible modus operandi that leads to superior performance in the process. According to Bergman and Klefsj¨o(ibid.) there is four kinds of benchmarking: • Internal Benchmarking - Comparison with the same process at other sites or another department within the same organization or corporate group. • Competitive Benchmarking - Comparison with the same process at a rival company. • Functional benchmarking - Comparison with processes at an excellent company in similar business area or a company performing similar activities. • General Benchmarking - Comparison with processes at a company that is the best company known irrespective of business area. According to Bergman and Klefsj¨o(ibid.) benchmarking can be done in 6 steps: Plan - search - study - analyze - adapt - improve. In the planning step, deep understandning of the own process is gained and key success factors are measured. The searching step is to search for a suitable organization to compare with. Study the process abilities and analyze the difference to the own process. Analyze the cause of the differences in both processes. In the adapt step, choose the best action to take in order to improve the process and adapt to fit with the own environment. Improve the own process by implementation of the action and measure the performance of the new modified process.

In this project, the comparison was done by internal and functional benchmarking. To find other suitable companies to compare processes with, a selection criteria was defined. Companies with assembly processes, that produce low volume or High Mix Low Volume, within or in connection to vehicle industry and that has high quality demands on their products.

3.6 Data Collection In the seven tools of improvement, that according to Bergman and Klefsj¨o(ibid.) was compiled by professor and quality-guru Kaoru Ishikawa in the mid 60’s Japan, data collection is the most important tool because of the need for accurate information to lie as a base for further quality improvement. The collected facts must be relevant, reliable, it cannot contain flaws or be misleading in order to benefit the upcoming analysis and work towards assuring quality. Before collecting data, a clear purpose with the collection is needed. • What is the quality issue? • What facts needs to be collected in order to illuminate the issue? The authors suggests that by answering the two questions, a clear purpose can be received. In this thesis project, data was collected through qualitative methods such as interviews, observations and study visits. Quantitative data on quality defects, scraps, risks of quality issues and costs was collected. By answering the two questions named earlier, and by connecting to the main problem description, a purpose for the data collection was defined.

15 3.7 Process Failure Mode and Effects Analysis Process Failure Mode and Effects Analysis (PFMEA) is a qualitative analysis method widely used in in- dustry in order to analyze a process by systematically scan the function, failure modus, failure reasons and the consequences of failure. According to Bergman and Klefsj¨o(2012), PFMEA is well suited in the early stages of product and process development work. The purpose is to investigate how to meet the demands of the market with regards to quality by preventing errors on the product caused by the production process. Bergman and Klefsj¨o(ibid.) also suggests that sometimes a quantitative analysis is used, to get a numerical value on the criticality of the risks which in turn leads to the possibility of prioritizing risks for error. The value is commonly calculated by scoring the variables O: occurence, S: severity and D: detectability of the risks for error on a scale from 1 to 10, where 1 is low risk and 10 is high risk. The product of the three variables is the quantified Risk Priority Number (RPN). An RPN value above a predefined limit indicates that measures is needed to be taken to prevent the way of error. After measures is taken another RPN is evaluated with the assigned measure in taken into consideration. If the second RPN is under the predifined limit, the risk is considered to be dealt with and the measure can be finalized.

In this project, the result of a PFMEA done previously at Scania was analysed in order to find what risks to expect in the assembly production at the studied work station and product. Risks that got the first RPN number over predefined limit were studied and put into categories. Secondly, risks that after measures is taken still got RPN over the limit was further studied in order to find improvement points.

3.8 Observation According to Yin (2018) there are six main sources to data collecting and two of those are observations:

• Direct observation • Interactive observation Tjora (2016) define observations as a method to analyze people on what and how they do certain things. Observations has been a part of data collection through out the entire thesis project. In the beginning of the project, it was concentrated to a direct observation to gain knownledge and understanding of the current situation, a objective observation. When the understanding of the current situation has increased and the purpose is clear, a more interactive observation was conducted. Interactive observation is when the observer can interact with the observed, to create a discussion for a deeper understanding and it was used frequently at the study visits. Together with documentation which is also a main source the results of observations could then be analyzed. This is a advantageous method according to Yin (2018), who mentions that of all the six sources, there is no method that is better than another. They are suitable for different purposes and situations, the best way is to use a combination of all six methods because their weaknesses and strengths in different situations could complement each other.

3.9 Study Visit The purpose for study visits was to observe other methods for quality assurance for similar products and was based on interviews and observations. Gathering of information within Scania has been made by study visits at a couple of departments in S¨odert¨alje.The first visit within Scania was in the Smart Factory Lab on the 17th of September 2019. A demonstration of new technology of quality assurance regarding assembly, logistic and educational purpose presented. Further visits was conducted at Engine Assembly on the 2nd of October and at Chassis Assembly on the 24th of October.

To gather information outside of Scania and see how other companies are working with quality assurance,

16 study visits at other companies have been conducted. A study visit at Volvo Group Trucks Operations (VGTO) in K¨opingwas done on the 1st of November. In K¨oping VGTO has their powertrain production, producing gearboxes for Volvo’s buses, trucks and loaders. The visit was conducted for two hours focused on assembly lines and quality assurance. The second study visit was also within Volvo Group, Volvo Con- struction Equipment (VCE) in Arvika. The site in Arvika is where Volvo has their main production of wheel loaders and also produces customized machines. The visit in Arvika was conducted on the 21th of November during the morning to late afternoon.

3.10 Interview According to Tjora (2016) interviews are the most commonly used method for data collection and is also a method to later interpret and analyze what people are saying. There are different types of interviews, the used interview methods were both unstructured and semi-structured, which are used for different purposes. In the beginning of the thesis, unstructured interviews was used to gain knowledge of the current situation and to determine the workload and scope of the project. The purpose was to get into the project quickly and understand the problem, thus the answers were not analyzed. It is stated by Bohgard et al. (2015) that unstructured interviews are best when the interviewer is lacking information of the situation. But the downside of unstructured interviews is that it could lead to important questions and aspects being missed, according to Andersson (2001).

Semi-structured interview is a combination of the unstructured and structured, it is to create discussion during the process but at the same time focusing on the topic, for this some adjustment during the interview can be done. This type of interview was used when a certain amount of knowledge for the project has been gained, to be able to acquire the specific information and answers (ibid.). The interviews together with study visits are then analyzed to find similarities and differences.

3.11 Evaluation of Alternatives After the data collection it was time to evaluate the previous gathered information. These were the results of observations, interviews and study visits. The purpose at this point was to summarize the product of earlier stages and evaluate which was relevant for the project and passed on to continuing the work. The risk categories that had generated from the PFMEA was used to categorize the alternatives to see which of the problems the respective alternatives would solve. New concepts or alternatives was also taken into consideration, by searching for another version of the collected alternatives or by combination.

The evaluation of alternative solutions lead to some issue. Issues regarding cost and the layout of low- volume processes. As a result of the issues, more delimitations to the solutions were added to this stage of the thesis: • Collaborative robot will not be taken further into finalization.

• Quality gate will not be taken further into finalization. The reason for the two additional delimitations is due to the type of the layout for low-volume processes. Low-volume processes are most preferable as fixed layout, and the two mentioned solution required some sort of line flow layout to be taken into consideration. The cost and the complexity of the solutions are also the reason for delimitations.

17 3.12 Finalization After summarizing the solutions and alternatives, the solutions were then taken further into the analysis. The theoretical framework were used as a base for the analysis, the theories are those of Quality, Quality Assurance and Lean Production. To analyze the solutions in consideration of cost, quality and flexibility. Supplier and manufacturer of the different solution were contacted in order to get a estimation of the cost. Some of the suppliers and manufacturers were difficult to get in contact with and could not give an estimation of the cost. Supervisors and colleagues were then contacted to gain their knowledge and experience of previous similar cases. The solutions could then be estimated to finalize and deliver as a complete solution.

3.13 Reliability It is stated by Burell and Kyl´en(2003) that reliability increases with more support of gathered data but only to a certain point. The point is where the growth of reliability starting to cease and stabilise, and that is when gathering of data does not affect the results and the focus should shift to analyzing the data. The quality of a research project is important and according to Tjora (2016) reliability is one of the factor that reflects quality. According to Saunders, Lewis, and Thornhill (2009) and Bell (2006) reliability a way to measure how well the result can be repeated to get the same output.

Saunders, Lewis, and Thornhill (2009) mentions four risk factors regarding reliability and the risks are connected to the human factor. It is related to factors such as misunderstanding and misinterpretation of instructions and questions and also anonymity. To handle risks when gathering data and to increase the reliability, for example for interviews, the questions were constructed beforehand to minimize the risk of misunderstandings. It was also explained that the answers would be anonymous to minimize the risk of biased answers. Overall data collection was conducted in communication and discussion with the supervisors to minimize the risk of doing it the wrong way and collecting the wrong data.

3.14 Validity As stated by Tjora (2016) the second factor that reflects quality is validity. Saunders, Lewis, and Thornhill (2009) mention that the two aspects together are important. Also stated by Bell (2006) high level of reliability does not means high level of validity, but high validity possible lead to high reliability. Validity means whether the investigation are what they seem to be and that data analysis measure what they intend to measure. Also determine the analyzed results and how it can be generalized (Saunders, Lewis, and Thornhill 2009). To acquire a high level of validity during the thesis, different type of data gathering methods have been used. Several observations and interviews at several different places to cover diversity. Also documents and historic data from colleagues, which sometimes were complex to determine the validity level. But at the same time those results are constantly questioned, analyse and discussed together with supervisors to evaluate and reach a high level of validity.

18 4 Current State

The Current State section holds the result from this thesis projects data collection regarding the current quality assurance methods and technical equipment used today in the existing low-volume process.

4.1 Assembly station layout The layout of the studied assembly station today is illustrated in Figure 5. There are two parallel assembly stations with separate monitored controlled power tools.

Figure 5: Example of low-volume layout.

4.2 Order system In the order system, the assembly order is started and a listing of the included parts is printed out. The listing functions as instructions for what parts to pick from storage and for the order of which the parts are assembled.

4.3 Controlled nutrunner with socket and bit selector The nutrunner used in the assembly station is an electric power tool that is controlled through the socket selector, a docking station for the sockets that when a specific socket is selected from the docking station, a predefined value of torque is sent to the nutrunner. When the assembly operator is pressing the button on the nutrunner, the nutrunner applies the given torque and then stops. A stacklight, red-yellow-green, communicates the status of the screwing operation. Red light indicates that there is something wrong, yellow

19 light indicates that the nutrunner is operating and green light is indicating that operation is finished and the applied torque target is reached.

4.4 Checklist As a result from the PFMEA performed by production engineers at Scania. Critical items and activities in the assembly process has been identified and compiled into a checklist for the assembly operator to use as a part of the assembly instructions. The items and activities on the list are the ones that has not been secured with technical equipment or methods of today. The activities are crucial for the quality of the gearboxes functionality and lifetime. Next to every instruction on the list there is a check box for the operator to put a cross on, by doing that the operation is confirmed to has been performed correctly. At the end of the list there are lines to sign the ID number for each individual gearbox, date of the day and who has assembled the gearbox. That is to assure that all steps are done and the purpose is to function as signature for Right from me.

4.5 Hydraulic Press The press that is used in the studied assembly process is a press that is only monitored by the applied pressing force. The press is used to assemble axles, bearings, seals and more.

4.6 Material Handling Material picking operations is done in a storing shelf, common for both assembly stations at the studied line. The items in the shelf is, with a few exceptions, sorted somewhat by the items chronological order in the assembly procedure. When visually similar items is used in the assembly they are placed apart from each other in order to not risk that the wrong parts are picked. Picking items is done by hand with the help of the printed listing of items that comes with the order. Each item has an individual item number for each assembly block, all parts are picked in one round and placed on a transportation cart.

4.7 Material transportation cart In the material handling and picking operations in the assembly area, a transportation cart is used to trans- port parts from the storage shelf to the assembly work station. As mentioned before in the subsection Material Handling, the items for each assembly block is picked and placed on the cart by the operator. The cart also functions as a portable workshop bench on which tools can be temporary stored between operations, sub assembly parts from earlier assembly blocks are temporary stored waiting to be assembled.

The cart is a two level, hand pushed, wheeled cart with dimensions of approximately 120x70x90 cm. The table surface is a black rubber structure which gives additional friction as support for the items placed on the cart to be still on the cart table. The rubber surface protects the items from outer trauma and also lower the noise from items vibrating against the surface when the cart is moving. The sides of the table are open with no additional edges that constrain items on the cart table.

4.8 Current Quality Assurance The current quality assurance equipment found in the studied assembly process is test rig, leakage testing and checklist with critical parts and activities. The existing equipment is testing equipment used to check for quality errors after assembly is done. Checklist is used as guidance and instructions on the activities and parts that has not yet been secured with quality securing equipment.

20 To map the current state with regards to the ability of securing quality and what risks to take measures against in the studied work station, the results from PFMEA, amounts of quality risks and RPN values are presented in a Pareto diagram in Figure 6. Due to classified information, values are censored. The current largest group of risks are identified in the part picking activities, followed by part placement and assembly activities.

Figure 6: Pareto diagram of current quality risks in the studied work station

As the studied work station is under development. some of the risks has been dealt with and measures are planned to be taken. Therefore, from the same PFMEA document, risks that was still given high RPN after measures are presented in a Pareto diagram in Figure 7.

Figure 7: Pareto diagram of remaining quality risks after measures in the studied work station

Further, In order to tell what risk group that is the most critical to act on and to eliminate with quality

21 assurance equipment, the mean RPN by risk group was calculated and presented in bar chart of Figure 8 for the risks identified.

Figure 8: Bar chart of mean RPN before and after measures is taken against most critical risks

According to the supervisor at Scania, there are currently four main components in the work station that functions as quality assurance tools today. The components are a leakage test, test rig, check list and nutrunners mentioned earlier in this section. The leak test and test rig investigates the presence of quality issues and can detect most of the possible failures. The issues that are hard to detect in the leak test and test rig are compiled into the checklist to alert the operator on critical items and activities.

4.8.1 General quality risks From the analysis of the current quality risks in the low volume assembly process studied, five main risk groups were identified. The three biggest risk groups are part or item picking operations, placing or assembly related risks, and risks associated with the use of different tools in assembly. • Item/part picking operation risks – Wrong part – Wrong number of parts – Forgetting parts • Item/part assembly placement operation risks – Part misaligned – Part damaged in assembly – Part not properly secured with intended placement • Tool usage risks – Part damaged by tool

22 5 Result and Analysis

The Result and Analysis section holds the result from this thesis projects data collection regarding the current quality assurance. The results from the conducted study visits, investigation on what methods and equip- ment there are used on the market. Furthermore, the section also contains the concepts developed to make improvements on quality assurance in low volume assembly for the future.

5.1 Study visits The study visits were divided into two categories, one for internal within Scania in S¨odert¨aljeand a second one for external outside of Scania. The visited places within Scania had a wide range of variety, included chassis and engine production to new technology testing lab. The first visit was at the Smart Factory Lab, the second took place in engine assembly department and the third within Scania was conducted at chassis assembly department. The chosen visits outside of Scania was at the competitor Volvo Group. Therefore, the fourth overall visit was conducted at Volvo Trucks Operations in K¨opingand the fifth place was at Volvo CE in Arvika. The main purpose was to see how other departments and companies are working with quality assurance and the equipment they use.

5.1.1 Smart Factory Lab The activities that build toward a smart factory involve digitalization and connected technologies. These activities can be found around Scania. The Smart Factory Lab is a prototype area for these activities. The Smart Factory Lab are working with a wide range of solutions that can improve the cost efficiency of Production and Logistic. Scania’s moving the truck and bus production towards the Smart Factory vision. When the processes are standardised, and the technology is connected, it will be able to collect and analyse data that can help to predict the future and prescribe action. At the Smart Factory Lab a interactive demonstration where everyone can inspect and try out the technologies is provided. The visit was mainly focused on observation of the presented technologies, and focused on solutions for quality assurance, as following:

• Pick To Light (P2L) • Pick To Voice (P2V)

• Pick By Tablet (PBT) • Pick By Vision (PBV) • Collaborative Robot

• Projected Vision

P2L, P2V, PBT, PBV are systems aimed for warehouse or operations including material picking. It is a technology designed to improve accuracy and efficiency method of paperless picking, putting or sorting and assembling products. At the same time also decrease the labor of the worker.

P2L, a guidance system that send signals for example to the storage shelf, and then indicates by light which parts are supposed to be collected. P2L can interact with other existing management systems or host systems but also be used as a stand alone solution. For example together with a operating system of assembly, the worker initiate the process of the station by scanning a barcode or QR-code. The system then lights up, and illustrates a path to guide the worker to the indicated location. Depending on how simple or complex the chosen P2L system is, it could then also indicate how many items that should be picked. The

23 worker then pick the pieces and the confirmation of the task are also depending on complexity, it could be done by pressing a button to turn off the light or by a sensor that is automated. The system then continues these processes for each operation until the assembly is completed.

P2V, also a guidance system that can cooperate with other systems. This system requires a headset with a microphone and optionally some type of scanner. It works by a voice command that give the instructions of the process, on where the operator has go, and then which components that has to be picked and also how many. Further, to confirm that the activity has been processed, the operator has to speak the part’s number. It does not have to be the entire number, but only for example the last three digits, thereby the system is controlling if it was the right part. An alternative to speaking for confirmation, a scanner could be synchronized and used to scan the barcode of the parts to indicate that the correct one has been picked.

PBT, is an alternative, digitalized version of process order by paper. It could be a tablet or screen lo- cated at the working station and the picking place. It then list the part according to the order that need to be collected. The concept of a tablet is that the operator can carry around the tablet instead of a bunch of papers, and by just pressing on the screen to confirm the work instead of handling physical papers and pencils.

PBV, a new perspective and smart technology on how to handle picking operations. Order picking solu- tion together with smart glasses. It requires the worker to equip smart glasses, and it works by the worker will see a screen or display by those glasses. Guided by augmented reality, for example the glasses displays where the location of the material is and also a specific number or barcode of the material. At the location guided by the glasses, the glasses has a function to scan. By tapping the side of the glasses and look into the barcode associated with the goods, the glasses then scan and give a confirmation. The processes then continue until the loop repeats.

Collaborative Robot or Human Robot Collaboration was one of the presented demonstrations. There are different types of tasks that could be done by this solution. But the main purpose of the solution is that the operator is assisted by a robot, those two are working together side by side. The first demonstrated solution was a robot that is used as a assembly station. The robot picked up the main component, such as a housing component that others parts are assembled into. The robot then move into a suitable position for the operator to work on the component, and when the task is done the operator can then command the robot to move forward into next task. It could be that a part to be assembled under the housing, the robot then rotate the part so the operator can work, and this goes on and on. Another feature that existed within the robot was a type of memorizing ability. For example, a very tall colleague has worked on the station and it is time for another colleague which is not as tall to replace on the station. The replaced colleague can adjust the robot position, such height according to desired preference, the robot will then remember the position and move to the same position for the continuing orders.

Another solution in this category was a robot that handle the materials by picking and placing the parts according to the programmed solution. The solution could be in form of a traditional pick in place, the task is repeated according to fixed pick and place positions. But the solution could also be adapted into that the robot are deciding the picking materials by a vision camera or scanner. This are described by a mix of components are in a box, and when the robot are going to pick it first take a photo to search and scan the box. It is searching for the wanted part but also scan if the wanted part are defect or not to then decide its picking decision.

Projected vision is a concept using a projector to project display into a component instead of a white screen. Using a projector on a tripod or installed on the ceiling to project. This was demonstrated using a chassis component from Chassis Assembly department. The component is large and possess a lot of holes

24 for other parts to be assembled on. On respective holes and places that are needed to be worked on, the projected then lights up each place with a description of the materials that are require for the assembly. For example, which type of screws that are required and how many. On the side of the component there is also a working description or instruction on how to assembly projected.

5.1.2 Engine Assembly Scania’s Engine Assembly or also internally called DE, is located in S¨odert¨alje.Scania has also a assembly facility in S˜aoPaulo in Brazil, but this facility in S¨odert¨aljeis the main production assembly of Scania’s engine. Scania are producing a wide range of products at the engine facility. Assembly of 5-, 6-cylinder and V8 engines for trucks, buses and also industrial and marine applications including testing and painting of those mentioned.

At the visit two process engineer were followed and the authors were guided through the engine production. The processes of the assembly were explained and how the department are working with quality assurance were also shown and explained. The visit was conducted by observation. At the beginning of the process was a shown a tools handling system solution, Controlled Power Tools and these were used all around the facility. Continuing the process line a station with a robot cell were described as one of the quality assurance system between stations in the middle of the production. The robot cell interact with a vision system to control and check the quality of the product. A vision system also exist independent of other system on the line. Another solution that were described by the engineers was quality assurance for variation. It was a solution using a fixture together with some sensors and a QR-scanner. Therefore the results of this department visit were four different solution of quality assurance, as following: • Controlled Power Tools • Robot Control Station • Vision System • Fixture Controlled Power Tools is the same solution that are being used at the current studied assembly station, described in 4.3 Controlled nutrunner with Socket and Bit Selector.

Robot Control Station is as previously stated a robot cell station that are being used to carry out the quality check. At this station the robot is equipped with a QR-scanner and laser distance measuring device. What it does is that, it is first checking the distance between two points of the prior assembled parts to control if it is within the given interval, and by that confirm if it was assembled correctly. The QR-scanner then search for QR-codes on the assembled parts and then scan those to also check and confirm if the parts that are attached to really are supposed to be there, for example the part number are the same as in the working instruction.

Vision System that are being used at engine assembly are both associated with robot station and inde- pendent. Despite that the vision system is being used together with another solution or is separate from it, the function of the vision system is still the same. How it was illustrated and explained was that, after the Robot Control Station has done its task and before sending the product forward the line, an additional quality assurance was done. It was the vision system taking pictures of the whole product and also at some specific points to then compare it with a reference picture on how it should look. If no deviations were detected or the product differ from the reference data the product may pass otherwise the line would stop. Another process that used the vision system was at a station that a robot was applying silicon to a component mentioned. The vision would then again take a picture to compare. At this process it was comparing pictures contents

25 regarding the silicon applied, such as the pattern and thickness. By this it could be stated that the vision solution is heavily dependent of data which the two process engineers also pointed out.

Fixture was a solution that the engine department had created. The included components of the solu- tion are more than just a fixture, it also included a sensor, scanner and spybox. But for the simplicity and because of the main component being a fixture, thus the solution is called ”Fixture”. The solution is a quality assurance regarding variation handling within the production. At the inspected station at line the solution was used for assembling of pumps. How the solution worked was that the assembler had to place the pumps in the fixture before assembling it. When it is placed on the fixture, the sensor then communicate with the spybox if it is the correct pump that is to be assemble. This is because the sensors are specific placed for each variation of pumps, so different type of pumps will activate different sensors. The spybox would then indicate green or red light depended on if it is ok or not ok for the process to assemble the pump at that moment. The mentioned scanner is also used for some occasion, for a special type of pump marked with a QR-code, and for a specific variant of engine to really ensure the right pump is installed. The system then require both activated sensors and a code scan.

5.1.3 Chassis Assembly Scania’s Chassis Assembly, internally called MS, located in S¨odert¨aljebuilding 230. In S¨odert¨alje,MS is one out of four final assembly factories within Scania producing truck and bus chassis for internal and external customers all around the globe.

For this visit a quality manager at the Chassis Assembly was followed through the line production of trucks. The manager explained that the assembly processes are mainly manual but with some supporting systems to assure safety and quality. The production begins with an order in the form of a bunch of papers, an instruction manual on what type of truck to assemble. The manual also contain a checklist for some of the work stations, to control and check for crucial steps or parts in the assembly. This instruction manual follows the product on the line through entire production. To ensure that the work has been done correctly, and sign on ”right from me”, the operator use a stamp to sign the manual on each required station. Later at the line Controlled Power Tools were also used, but only at some few stations. When the production is done and the whole truck is completed, before shipping to the customer, a final assurance is done in a quality gate. There is some special cases as well, some of the products are also randomly selected for a quality audit, going through more of a complete testing process at the After Line Quality Gate. The quality solution results of the visits are thereby listed as following:

• Controlled Power Tools

• Personal Stamp • After Line Quality Gate

Controlled electric nutrunner is as mentioned in the previous section, the same solution that are being used at the current studied assembly station and Engine Assembly, described in 4.3 Controlled nutrunner with Socket and Bit Selector.

The personal stamp is used in combination with the checklist and instruction manual. The worker or personel has to do special training and educate oneself to obtain the stamp. It is a physical stamp that is being used at the line to give the assembler more responsibility but also to make the assembler observant on that the process is important. How it is used is simple, when the parts are assembled on the station that require the assemblers stamp, the person that has done the job make a stamp in the manual to ensure that work was performed correctly. The result could then be traced back to the owner of the stamp if any issue would

26 arise. A worker is not allowed to stamp others work, because if the worker is not careful and really ensure the quality of the job when stamping it, defects can be sent further down the line. The assembler will then lose possession of the personal stamp and not have permission to perform the specific job.

After line quality gate is an area that some of the products are going through. This gate is different from the gate that is located at line. The difference is that at line, all products are passing that quality gate and that gate are checking for example if all the crucial parts are assembled and overall appearances. The after line quality gate is as mentioned for randomly selected products to be stationed here for a complete testing session. The testing covers complete performance testing, the trucks and busses are checked thoroughly and also test drove for approximately 100 kilometers. When the testing is done, the product then goes back to get some finishing touches, for example repainting.

5.1.4 Volvo Trucks Operation, K¨oping Volvo Trucks Operation is part of the Volvo Group. Volvo is a Swedish multinational manufacturing company with the core activity is the production, distribution and sale of trucks, buses and construction equipment. Volvo also supplies marine and industrial drive systems and other services. The conducted visit for the thesis was in K¨oping.The facility in K¨opinghandles powertrain production of Volvo’s trucks, busses dumpers and marine transmission solution for Volvo Penta. The site is described to be the ”Center of Excellence” within their area of transmission solutions and has today approximately 1600 employees.

For the visit an engineer was followed through the production line, the assembly line of gearboxes. It is described that the facility has a very high level of automation at the site for manufacturing of parts, but the assembly site are mainly manual work based processes. The main line was followed through and explained, with high product variety and high quantities produced on the same line, and quality is said to be the top priority. In the entire production line, VGTO are using a system explained as an Overview System to ensure the quality and production processes. The main line starts with a pre assembly station and already at this stage some quality assurance systems is used. At this station, and also further down the line, a P2L and Vision System is used. Other than those two the engineer told that an additional solution called Presence Sensor also exist at pre assembly due to a repeated deviation in the past. Controlled Power Tools exist in the production, similar to the one at Scania. Along the line in about the middle of production at the assembly of control units, a Laser Marker solution is used to align gears to ease the process. At the end of the line a common Quality Gate for all produced product are located, to ensure the product quality before shipping.

In the K¨opingfacility there is a special line or station for low volume assembly. At this station VGTO are producing electric gearboxes since 2016. The reason it is special is because of the electrified gearbox assembly and that the line is producing products in low-volume in a fixed layout. At this line, the quality assurance methods used are almost the same as the main line. The Overview System, Controlled Power Tools and P2L. Other than those there is a hydraulic pressing machine equipped with a system to inform which instruction order the machine has to do through a Socket Docking station. Explanations of the solutions identified within VGTO in K¨oping is as following: • P2L • Controlled Power Tools

• Vision System • Quality Gate • Presence Sensor

27 • Overview System • Socket Docking The P2L that is being used at the K¨opingsite is a variation of different P2L systems, a range from simple to complex P2L as described in 5.1.1 Smart Factory Lab.

Controlled Power Tools is the same solution that is used at the current studied assembly station, as previous described in 4.3 Controlled Nutrunner with Socket and Bit Selector.

Vision system is also similar to the previous mentioned with images taken and analyzed to reference data, as described in 5.1.2 Engine Assembly.

Quality gate is the station to ensure the crucial parts are assembled and overall appearances by follow- ing a checklist, as described in 5.1.3 Chassis Assembly, After line quality gate.

Presence sensor is as mentioned a solution used in pre assembly, a solution that was created due to re- peated deviations. The deviation problem was that the assembler often forgot to assemble the needle roller bearings to the pre assembled part. To handle and solve the deviation, the engineer explained that they had created a small box and attached a presence sensor to it. A presence sensor, for instance the inductive type, is a sensor that can tell if a metal object is present or not in front of the sensor. When it is time to assemble the bearing on the axle, the instruction then indicated that the assembler has to put the bearings in the box to activate the sensor, and immediately after assemble the piece before the next operation can be performed. Where the presence sensor equipment is placed on the work station make it possible for controlling where the assembler and the part is at a specific time. The placement of the equipment also decreases the risk of misplacing the part, in this case the bearing, because the nearest place to put it after activating the sensor is in the intended assembly position on the product.

Overview System is what the engineer at VGTO explained to control their production line. The system is divided into three parts that covers different areas. The first one is a system that initiated the order and production of the product and following the production through the line, such as the instruction manual in form of papers or updated screens at line. The second is a system that tracks the product, telling the status and where it is in the production to monitor the flow. Lastly the third one is the one that is handling the TAKT-time. All the three systems together gives the Overview System which collaborate and provides flow to the production and processes. With help and guidance by the Overview System, operators know what, how and when to build the different products.

Socket Docking is associated with the hydraulic pressing machine at VGTO in K¨opingas previous men- tioned. The docking station communicate with the pressing machine, it provides the pressing machine the information to perform the correct pressing operations. Each socket on the docking station represent a specific program for the press to run. It then means that when the operator take a socket out of the docking station, the press will automatically know what to, which installation and parameters to perform on the processing piece. The required task for the operator is to put the socket in place and the piece in the machine.

5.1.5 Volvo CE, Arvika Volvo Construction Equipment in Arvika is Volvo’s main global production site for wheel loaders. They produce thousands of units per year and deliver worldwide. VCE also manufacture components for the wheel loaders. The components that they are manufacturing is rear frame, front frame and lifting frame and the rest of the parts, most ordered from Sweden, are delivered to Arvika for assembly. The products assembled in Arvika are divided into three categories of wheel loaders with different load capacity: medium, large and

28 heavy. All of the products are considered to be low-volume products but for heavy class, there are even fewer in production and can therefore be considered to be extremely low-volume. Today VCE has approximately 900 workers in Arvika and like other organizations within Volvo, they are working with and build upon principles of Lean Production.

The visit was conducted during early morning to the afternoon and covers how the quality department and the production of Arvika is working with quality. The quality organization is divided into four sections, Project Quality Manager Operations (PQMO), Quality Assurance, Quality Engineering and Measuring & Audit. The quality organization manager and manager of each section were followed during the visit. The visit was based on semi-structured interviews and observations.

PQMO is mainly focused on projects, in the pre Start Of Production (SOP). PQMO work consist of as- suring that the quality processes including tools and methods in product projects are followed according to Volvo’s global Production Quality Assurance Planning process. Support the PFMEA work within the site and secure the communication, update and follow up the plan for each project. Define production quality requirements for input to the projects and align the quality requirements in purchasing projects.

Quality Assurance work both pre and post SOP. In the pre SOP the work is support based. Post SOP, the focus is put on performing quality control and audits on incoming material, supplier quality assurance and measure parts in cleanliness lab. Flagging for occurring quality issues on purchased material and stop production if needed, and also handling quality gates in assembly line.

Quality Engineer work is to handle the development and maintain site procedures for quality inspections and control. Continuously analyse data from production quality control, field and dealer data such as assem- bly, fabrication and supplier data. Also support the assembly and fabrication with quality improvement and problem solving.

Measuring & Audit is working with performing controls and audits on prototypes. Perform product and structure controls and audits of machined products. Ensure calibration of measuring and torque tools, and ensure reaction plans are followed and that quality problems are contained. That also including flag quality issues on self produced material and to stop production if needed.

All of the sections mentioned above are working close together to ensure quality and quality assurance. Both the manager of quality organization and manager of each section states that quality and quality as- surance are essential and much focus is on proactive work. For the daily meeting a sheet is printed and handed out which contains the information of previous day’s deviations and the status of those, to discuss and find the root cause on how to handle them. This is to give an overview of the status on the current situation on site. At the line the quality assurance is mainly based on checklist within quality gates, which is performed by manual work. The medium line has one quality gate and the large line has three and the gates are manned by one operator each with specific checklists. The checklist contains general information, critical points to be checked and also critical parts. The problem within the quality gate is that both the controller and assembler are working at the same time which can sometimes be crowded. Another deviation that cause problem for quality is that sometimes workers skip reading the standardized instructions due to experience and habitude. This is something that they are working very hard with in Arvika to get everybody to know how important quality is. It is also stated that all deviations are tracked and stored into statistic data, the deviation is given a code which could then be analyzed through the data. The data is divided into categories and stations in order to highlight and make improvements in the different fields.

29 5.1.6 Analysis Study Visits The analysis of all the study visits will be based on theories of Quality, Quality assurance and Lean Produc- tion. Analysing the existing solutions to the current quality assurance and risk categories in terms of cost, quality and flexibility.

All the visits has been to facilities that work with assembly of products except for the Smart Factory Lab at Scania, which is a testing area for new solutions and technologies. Regardless, common for the companies and facilities is that quality is a high priority and they all have high production quality. They saw quality as a crucial matter and something that is very important for the customer, because of the product that are being delivered represent the companies. For the customer quality is something that is expected and thus products must be delivered free from fault, from incoming goods and all the way through the processes to the end customer. Securing quality is represented by doing ”right from me” and elimination of wastes according to Lean principles for ensuring a high level on the quality dimensions. Both Scania and Volvo are working very hard with Lean Production by standardized work, work in a proactive manner, strive and drive to accomplish high quality goals. The companies has standardized quality control during assembly, but the difference is that some has automated control, other has manual control by manpower and some both. This enable high quality already during the line and does not allow deviation to be passed on. This is the result of a long journey of work within each company, work on culture and the base level that the company is built upon to create a learning and continuously improving organization. The tools and solution that the facilities are using for quality and creating value for the customer, company and product.

The result of the visits showed that all of the facilities are working with similar methods and tools. It is just some minor details that differ from each other. The tools and equipment being used depends on the manufacturing and assembled product. By that means the main attribute is the volume of the product which in turn represent the scale of investment that can be allowed with regards to production cost. For such Engine Assembly at Scania and VGTO in K¨oping,both mainline has high capacity and are producing in larger quantities. Which allows them to have expensive, high-tech automated equipment and tools such as robots, vision systems and customized solutions of fixtures and sensor apparatuses. Even though the investment for low-volume line is limited, quality assurance and a high level of quality is still as necessary. These necessary tools and equipment are to acquire the minimum quality, and represent the solutions that all the places has in common the P2L, Controlled Power Tools and checklist for crucial and critical parts. P2L to ensure the picking materials from start and removing many unnecessary waste for example motion for the worker, transportation for the parts and extra processing. Controlled Power Tools to help the assembler apply correct torque and receive visual feedback if it is applied too low or too high. Checklists is the minimal and easiest form of ensuring that the work has been done correctly. Overall the purpose is to not produce any defects by investing in a lowest high to save cost of rework and scrap.

In Terms of Cost To compare and evaluate how efficient and which are suitable for Scania a cost estimation has been made for the solutions, listed in Table 1. The cost estimation was made by interviews of the visited places and discussion with colleague that has the experience with purchased for previous projects. These approximation are rough due to details and purpose of each project. But this would give a indication and overall view of the solutions.

30 Table 1: Cost estimation of solutions IT System Estimated Cost [SEK]

MONA 9 600** EBBA Resource 70 000 (20c) DIDRIK 500 000

Equipment Quantity Estimated Cost [SEK]

Pick 2 Light 20c 40 000# Pick 2 Voice 20c 50 000# Pick By Tablet 20c 20 000# Pick By Vision Glasses 1 15 000# Vision System Camera 1 150 000# Controlled Power Tools 2 860 000* Projected Vision 1 500 000* Presence Sensor 1 1 200# Socket Docking 1 5 000# Spybox 1 30 000#

(**) Monthly leasing cost of printer, monitor and computer (*) Includes hardware, installation and configuration (c) Quantity for material parts to be covered (#) Hardware

The IT System as shown are MONA, EBBA and DIDRIK which also represent the three parts of Volvo’s Overview system but the name used are what it is called in Scania DT. Breaking down each part, it is im- portant to mention that these costs are rough approximations. Because of the cost to implement the whole system for example for a high-volume line, are described to be much more expensive than the listed.

MONA is the first part of the Overview System that mentioned for Volvo, this initiate the order and give the instruction of which parts that are included. The minimal cost for this is just for printing out paper and listing production orders on a monitor which represent the hardware cost. That cost is roughly 9 600 SEK monthly leasing of printer, monitor and computer. EBBA is the second part to the Overview System which interact with the MONA to track where the product is and divide each assembly sequence to part and visualise it on monitor. But the listed EBBA Resource is the IT Resource cost from a project needed to get the P2L configuration and installation. This could represent the base requirement cost for the systems of P2L, P2V, PBT and PBV. DIDRIK is a optional solution and third of the Overview System that is not really required for low-volume purpose, it is of course preferably to have a TAKT system working on the assembly but due to limitations and cutting of every unnecessary cost for the start and time being of current state. The cost for the future if wanted to invest in TAKT is therefore approximately 500 000 SEK, note just for the similar production of the current state.

31 The rest of the presented equipment are mostly just hardware cost. It is described that every solution of the hardware often require some sort of IT integration and configuration. For stand alone of almost every solution a Spybox is minimum required connection, this also needs software and IT configuration work. The presence sensor and socket docking seem to be the cheapest solution just by looking at the Table 1, but the reality is that it require much more than just the hardware. As it is stated by the production engineer in K¨oping,their solution of presence sensor are connected with the Overview System which are the major cost for it. So the price are just for the holder cup and sensor tread but it require some kind of Overview System and software developed to function properly. The Socket Docking equipment was a specified requirement to the supplier when purchase order of their hydraulic press was put, so therefore the whole solution would require the cost of a new advanced hydraulic press. New press and together with the presented hardware cost of sensor tread would mean that the solution approximately goes up to more than 500 000 SEK depended on the chosen press.

Previously some necessary equipment and tools were mentioned to acquire the expected quality, and that would be solutions that all the places has in common. Which were the P2L, Controlled Power Tools and checklist. The P2L could be replaced with any other ”Pick” solution for the handling of picking risks, but it is the most common equipment seen. Controlled Power Tools to handle the place and assemble risk for tightening operations, and checklist to ensure the overall quality and for the crucial parts. Table 2 is the cost for the necessary equipment and tools for quality assurance in a low-volume assembly, like the one of current state.

Table 2: Example of quality assurance cost for a low-volume assembly IT System Estimated Cost [SEK]

MONA 9 600** EBBA Resource 70 000 (20c)

Equipment Quantity Estimated Cost [SEK]

Pick 2 Light 20c 40 000# Pick 2 Voice 20c 50 000# Pick By Tablet 20c 20 000# Pick By Vision Glasses 1 15 000# Controlled Power Tools 2 860 000* Spybox 1 30 000#

(**) Monthly leasing cost of printer, monitor and computer (*) Includes hardware, installation and configuration (c) Quantity for material parts to be covered (#) Hardware

To summarize the table as a whole is that MONA would represent the initiation of order instruction and that also include checklist. The equipment to handle the picking risks would need installation and configura-

32 tion from IT, and also a spybox. Therefore the cost of ”Pick” solution is a summarizing of EBBA Resource (IT), the respective ”Pick” equipment and a spyboxes. The current state as a reference would results in two setup needed, one for each working station. Therefore the summary cost of pick solution is two times EBBA resource, pick hardware and spyboxes. To quality assure 20 parts for each station. Lastly the solution for placing and assemble is the minimal that all has in common, the Controlled Power Tools. The cost overview of each section for the required solution are as shown in Table 3.

Table 3: Cost estimation of low-volume solution, current state example Order Initiation and Checklist Estimated Cost [SEK]

MONA 9 600**

Pick Solution Estimated Cost [SEK]

Pick 2 Light 280 000 Pick 2 Voice 300 000 Pick By Tablet 240 000 Pick By Vision Glasses 230 000

Place Solution Estimated Cost [SEK]

Controlled Power Tools 860 000

Total Solution Estimated Cost [SEK]

Total with P2L 1 149 600 Total with P2V 1 169 600 Total with PBT 1 109 600 Total with PBV 1 099 600

As shown to quality assure a line likewise the current state, regarding the two major from PFMEA and have a crucial control would require a cost or investment of approximately 1 100 000 to 1 170 000 SEK depended on the chosen solution. Now the highest and lowest differ 70 000 SEK, and as mention to save every necessary cost is preferable. The highest cost does not necessary mean it is always the best and the that lowest cost is always to prefer.

In Terms of Quality As mentioned before, each and every one of the solutions has its own pros and cons depended on the goal and purpose of the user and what wanted to achieve. In term of quality for the solutions, Table 4 below is listing the solution for the risks that it would handle.

33 Table 4: Equipment and its risk category Equipment Risk Category

Pick 2 Light Pick Pick 2 Voice Pick Pick By Tablet Pick Pick By Vision Glasses Pick Vision System Camera Pick & Place Controlled Power Tools Place Projected Vision Pick & Place Presence Sensor Pick & Place Socket Docking Tool

Quality of the solution is the reliability of it, and how well it handle the risks its suppose to handle. Reliability of the equipment are also linked to its disadvantages and advantages. Every solution has its own pros and cons. For that reason it may be difficult and not preferable to make a choice only based on the cost. Therefore, to determine which equipment are suited for the purpose, pros and cons of the equipment are listed as following: • P2L is the most commonly used solution for material handling. The pros of P2L are that it gives a overview and visualisation that are easy to follow. The equipment are easy to understand and not complicated. It is also flexible for product changes, the same equipment can be used to secure a new part. The cons of the solution is that it may not be suitable for parallel work, on a work space that the assembler share storage shelves. It may lead to confusion for which lamp belongs to who when the process require the assemblers to pick the materials at the same time. • P2V with the headset and scanner. The pros of P2V are the possibility for parallel work and high rate of ensuring the right picked part. The high rate is by the requirement from the equipment to both speak and scan the item to confirm the pick. The possibility for parallel work is because of that the equipment are independent of each other. The instructions given are individual and does not create confusion. The cons are the risk of being isolated and not being aware of the environment. Another one is discomfort, stated from a testing that Smart Factory Lab had conducted, most users of the equipment got a headache after a hour of use. • PBT using a portable tablet to follow a instruction. The pros of the solutions are the visualization that it gives and the simplicity. But this is more of a helping tool than a quality assurance. Therefore are the cons that it does not really ensure the process, it is just a digitize version of a list. Another liability is that the assembler need to carry it around which lead to one hand being occupied and limits the freedom. • PBV using a pair of glasses to perform picking tasks. The pros for this solution are also the possibility for parallel work and the flexibility for the users. Which provides the user hands free work and independent of another user. The same as P2V, the equipment leads to discomfort and headache. • Vision System using a only a camera or together with a robot. The pros of the solution are that it is fast, provide high productivity and repetition. Another advantages of using a robot is that it can

34 be adjusted to product changes and use for other purposes. For example when it is not required to perform the quality check anymore, most of the robots can perform pick and place operations. The cons of it are the cost of the equipment which are usually expensive, the installation of the equipment also require a lot of data and calibration. Complexity of the product also affect the solution, many parts close to each other and small spaces can be difficult to check. • Controlled Power Tools for the assembly operations. The benefits of the equipment are that it help the assembler to apply the right torque for the operations. It also indicate the level to tell the assembler if the torque is too high or low. The equipment is ergonomic and provides productivity for the assembler. The cons are the cost and reach ability in small limited spaces. • Projected Vision using a projector to guide the assembler. The pros of the solution are that it provides a clear visualization and overview of the process, also the solution is user friendly based on the testing that has been made. The cons are the sensitivity of the equipment, sensitivity to the environment and it also require much space. Sensitivity in aspects of the light and vibrations of the environment. • Presence Sensor is a option for the other solutions. The pros are that the hardware is cheap and can be use for both picking and assembly operation. The con is that it is not really a quality assurance but an extra way to ensure the tasks. • Socket Docking is also a optional solution, for the controlled power tools and the hydraulic press. A optional solution that is purchased along with the press or nutrunner. The pros of the equipment are the way it ensure the press or nutrunner, depended on which socket is selected the program connected to the socket is then automatically selected for the task. Therefore it also provide the right operation for the worker. The cons are the additional costs, it require a smart and compatible press or tool to connect with. Also costs of installation and programming to set the desired tasks.

Based on the pros and cons, it then reflects the equipment in term of quality. For recommendation there are two solutions that suit the purpose and handle deviations of the current assembly line. Recommendation for current state represent also for the future similar lines. The solutions are P2L and controlled power tools to cover the pick and place risks. The reason for P2L is because PBT as mentioned does not really ensure the process but is just a digitize version of a list. P2V and PBV provides parallel work which is preferable in this situation but because of discomfort and headache that affect the users, the solutions would not work. Because the health of the worker is top priority, the recommendation is then based on P2L. Controlled power tools because it is the only equipment that would ensure the assembly. That is due to vision system and projected vision not being suited for this type of production layout and also due to the complexity of the product. Presence sensor and socket docking for the press can also be used to additional secure the equipment but is not recommended at the moment due to it may not increase the quality assurance but only lead to more cost.

In Terms of Flexibility The presented equipment and solutions are, regarding flexibility almost all capable to be adjusted. Adjusted and flexibility in this context means that it does not require much time and work to adapt to the changing of the product. Majority of the solutions are depended on the software, so the work that would have to be done is hours of programming. The hardware for example for the P2L could just be replaced to another shelf. The one that could be depended on the specific product is perhaps associated with the hydraulic press. Depended on the chosen press at the purchased time, a more basic type of press could maybe only be worked on the specific product, then therefore need to buy a new one to adapt to the changes. Overall most of equipment can just be adapted by IT which is good in term of flexibility related to the wasted and Lean principles.

35 5.1.7 Conclusions The conclusion summarize the results from study visits and of the equipment that has been seen and evaluated. Aspects and key points for quality assurance regarding of the equipment and solutions. • Quality assurance’s equipment are expensive • Companies are using similar equipment and solutions

• Heavily software depended • Equipment are necessary for quality • Regarding cost, quality and flexibility the total solution with P2L is recommended

36 5.2 Interviews The interviews subsection holds the collected answers and personal views of the respondents on quality assur- ance questions as well as the analysis of the interview results.

5.2.1 Respondent 1: Quality manager, Chassis Assembly department The products that the respondent works with are complete trucks and bus chassis. The understanding of Quality is to deliver a product that fulfills the customer expectations on time and within budget. At present, the quality assurance is performed by checking for deviations on every truck or bus on specific locations in production according to a standardized checklist. Critical tightenings are secured with systems that can detect if screws and nuts are not tightened according to standard. The tightening data is also stored for each truck and bus at some stations where tightening equipment is connected to a monitoring system. Assembly operators do quality checks for some critical assembly activities on the trucks and busses and then fill and sign a quality protocol that is stored in a database. Random product audits is used on trucks and busses. Daily Torque Verification (DTV) which is a method used to make sample spot check on tightening work in order to find deviations and to see if the tightening equipment is properly calibrated and functioning correctly on a daily basis. There is a system for logging the deviations found on each product that is used for securing that no product is delivered to customer with a deviation that has been identified.

Quality assurance during production is critical according to the respondent. A quality deviation that is sent to the customer will damage the image of the company. After production, random audits should be enough to get a good indication of the current production quality at the moment. Current needs regarding quality assurance are more connected tools in production and improved traceability of assembled parts. In order to reach tough quality goals in production, knowledge and awareness is needed as a foundation with automation as a tool.

The respondents experience of the products quality at present is that quality is best in class and customer feedback regarding quality is really positive. The most common quality deviation in production is paint dam- age caused by human interaction. The most difficult deviation to detect during production is bad tightening and internal deviations in pre assembled parts.

The respondents view on how deviation handling works today is that the handling process works good. What the respondent is missing in the deviation handling process is traceability in production along with tools to help the operators in order not to miss any steps in the assembly.

If the respondent was able to make organizational changes in the deviation handling process it would be carried out according to the following: Workshop technicians on each area constantly follow up on deviations and create preventive actions. Product and process engineers work with improvements including quality assurance equipment needed in production. Repair team that repair deviations in production and after line. According to the respondent, quality assurance is continuously changed and developed in order to make improvements. There is ongoing work to improve the automation systems in production that will have big impact on ability to secure quality.

Root cause analysis is according to the respondent not performed as accurate as they would like. This is, according to the respondent, due to lack of knowledge on how to work effectively with root cause analysis. Within production, all trucks and busses are checked and tested the same way, with the exception to the products checked in DTV. After production there is random quality test in a product audit department. The tests is standardized and it is of great importance that the standards is followed in order to detect anomalies and trends that can tell if something is wrong.

37 Product variety make quality assurance more difficult and leads to higher demands on tools and meth- ods to handle part variants in production. Products with uncommon variants are the most usual products that deviations occur on. There are a lot of costs associated with quality assurance and testing. There is a quality gate department, a product audit department, repair department, maintenance department, upkeep and license costs on automation and traceability systems. Therefore estimating total cost of quality is tough.

5.2.2 Respondent 2: Process Engineer, Engine assembly department The products that the respondent is working with are engine products on straight and V8 line. Main re- sponsibilities are to adapt new products to the existing assembly equipment to secure quality. Todays work on quality assurance in assembly is coming from PFMEA work where a decision is taken if any additional quality securing equipment for variants and new parts is needed. If there is a need, the project is started, risk assessment is done and handed over to the project in order to purchase appropriate suitable additional equipment. Persons involved in the work is line personnel (team leader, position owner, group manager) and local production technician. The equipment used are code scanners, smart cameras, vision systems and different poka-yoke devices.

The respondents opinion about quality assurance is to secure quality in a profitable way during produc- tion in order to maintain happy customers after production and delivery. The general opinion about if today’s quality assurance is complete varies, the respondent cannot express what he thinks is missing or what would further increase quality.

Overall quality is high on engine assembly department and feedback from customers is positive.

The deviation handling of today is working really good according to the respondent. Intensive work on identified deviations in order to make them not appear again. Root cause identification is executed through group discussion with the persons concerned.

The respondent suggest that assembly is good when equipment is up and running with proper function- ing. To have reliable equipment is key in order to maintain quality in production. An example of a problem that has accrued is when equipment for securing variants stopped working. Product variety results in higher risks of mixing components up during assembly. Therefore, a need for variant securing equipment is present and equipment needs to be adjusted to fit with variations of parts in the different products.

5.2.3 Respondent 3: Production engineer, Volvo Group Trucks Operation, K¨oping In K¨oping,Volvo group has a production site where gearboxes for trucks, buses and marine drivetrain com- ponents with both manufacturing and assembly departments. Gearboxes are also sold externally for final assembly in vehicles from other companies.

In manufacturing, level of automation is high, industrial robots tending machines by loading and unloading material and the operators normally never touch the manufactured parts until the parts have reached the assembly stations.

Assembly is mostly done with manual labour, according to the respondent the quality is valued high. The priorities of Volvo is SKLEMM and stands for Security (S), Quality (K), Delivery (L), Economy (E), Envi- ronment (M), Human (M). Quality is the second priority which is also given much space for quality assurance equipment in production lines. At the main assembly line a high variety of products are assembled which puts high demands on quality assurance in assembly. According to the respondent, Volvo has come a long

38 way in quality work and is world leading compared to competitors.

Current quality assurance starts in the products design phase where design engineers and production en- gineers are working together with Design Failure Mode and Effects Analysis (DFMEA) to eliminate quality risks, that may come up in manufacturing and later assembly, at an early stage in the design process. When the team does not get any further with designing risks away, another cross functional group do PFMEA work to identify and take measures against risks in the assembly process. After PFMEA is finished, risks remaining can be secured by purchasing and installing quality assurance equipment if there is a need.

The most common errors, according to the respondent, is part picking errors that may result in wrong parts or wrong number of parts assembled on the product. Most such errors are later found in the leakage test or in the test rig where the final test is done before shipping. Errors because of operators forgetting to do things due to not thoroughly reading the instructions, or that errors are done intentionally by the operator also happens. As a whole, according to the respondent, the goal is to find errors as quickly as possible before the product needs to be disassembled for trouble shooting that costs much time and money when errors are found in final testing or if errors are found by the customer.

What the respondent think is missing in production today, associated to quality, is to make the data collected from production equipment accessible and visualized to the users in production. The way things work today are that if someone want to extract collected data, they need to extract, treat, manipulate and present the data to make it understandable in order to take advantage of the data.

5.2.4 Respondent 4, Production engineer, transmission assembly From a Quality perspective, quality of the equipment is of high value. Risks are identified and evaluated out of a quality and safety perspective, and with the equipment that has been purchased, the risks are eliminated if possible or reduced as much as possible. For every individual risk evaluation, if the found is critical with regards to the consequence, and cannot be forgotten or missed, measures is taken for securing both picking and assembly operations of the part involved in two steps. Risks of error with a milder form of consequence is secured with the end of line test rig that detect the error. For instance if the risk will for certain be detected further down the process and the consequence is that the product needs to be disassembled and repaired, the consequence of repair time is evaluated if manageable. The main priority is that no error can reach the end customer. In low volume assembly projects, the experience of the operator is a key factor for good quality, putting high demands on the operators to do ”right from me”.

Risks are identified continuously both in a proactive way before production and also in a reactive way for risks that are found on site in production. Every error is followed up to see if the risk of the found error has been investigated earlier. If not, the error needs to be evaluated in a reactive manner in order to be prevented and secured. The main tool for proactive quality work is PFMEA. Also during prototype test assembly, risks are identified and worked with before SOP which can be seen as a semi proactive method. The detectability of the found risks is further investigated and followed up by building specific errors in a product to see if the errors can be detected in the assembly process or during testing.

The quality and safety of the products needs to be high and the operators also still need high quality and high safety tools. Safety for the operators comes first hence safety of using the equipment always needs to be secured and this is done with simple solution to a certain extent. Maybe an extra evaluation is done to find simple solutions before purchase high cost solutions. Expensive and automated equipment that reduce human error can accomplish much but for instance automation and flow is prioritized low, instead demands

39 are put on the operators but still quality can be secured and kept high with simple tools when the product is sent from line. Different equipment solves different problems. For instance if the risk is that something is forgotten, then that results in a specific measure with a specific equipment. The equipment can then be clustered in groups together with the risk that is reduced or eliminated by it. For instance the risk of forgetting to pick a part can be solved with P2L equipment. Forgetting to pick parts is a common error. How big part of the budget that is associated with quality assurance in the current assembly line is hard to say due to the big subject and the many sections of quality assurance. There is quality assurance by purchased equipment, proactive methods such as PFMEA, standards, operation methods and many more components to it that integrate quality in many steps.

Now the layout is station based with a fixed station layout which means that the product is built in one place with exception for some pre assembly operations. Production has prepared the assembly sequence for a future balanced flow where the product is moving, and not completely in a fixed position, during the assembly. The current layout setup with two parallel stations provides flexibility when for instance an error is found in one station, the other station can be used in the meantime. Overdimensioning the equipment can provide some flexibility, for instance for the min/max torque in the nutrunners can provide room for changes. Overdimensioning the equipment is however a form of waste. For lifting aid equipment for instance, that can be specially designed to fit specific parts, is not as flexible for future changes regarding the product and needs to be replaced with another specially designed equipment. Nutrunners, press and P2L equipment are also quite flexible due to possible software changes. Another thing that makes equipment flexible is that equipment can communicate with each other through the spybox and the coded sequence programs. Changes in the P2L system may require extra lamps and software adjustments in the control system, depending on what equipment the P2L system should activate or inactivate. The nutrunners have their own control system and is by themselves programmable in order to secure tightening operations in programmable sequence.

5.2.5 Analysis of Interviews The analysis of all the interviews will be based on theory of Quality, Quality assurance and Lean Production. Analysing the existing solutions to the current quality assurance and risk categories in terms of cost, quality and flexibility.

All respondents see quality as a high priority and critical to the company’s identity. The respondents views on quality during production is that quality should be built in at an early stage in order to reduce waste and establish ”right from me” meaning to take a proactive approach towards quality goals. Therefore quality assurance equipment for helping the operators to do that is invested in. To learn from deviations is a success factor, in order to make the right decisions regarding measures to be taken in order to secure quality and make improvements. Products that get rejected, or sent to reparation stations after line, results in wastes in the form of rework or even scrap, which are mentioned by respondent 3 and 4 particularly. The products with errors that needs to be repaired also have a negative impact on the deliverance quality dimension for the product. What also can be seen is that quality assurance come with a high pricetag due to the need of different quality departments work and high cost testing equipment. In order to not overspend on quality equipment, decisions regarding needed equipment should also be taken based on lessons learned from deviation handling processes. The lessons learned can also be used to gain better results for reducing risks in future production development work in a proactive way. All respondents mention different Failure Mode and Effects Analysis (FMEA) variants that they use in the proactive quality work during product development to eliminate risks by in the design, but also to identify possible risks when the design is set in stone. Respondents also suggest that root cause investigation is an important method to use in order to take appropriate action against deviations at the earliest stage possible. Respondent 1 and 4 suggests that the root cause investigation can be performed better in a more structured and standardized way to reduce even more waste connected to bad quality. Respondent 4 also states that for low volume production there is a

40 bigger need for experienced and high quality operators who reduce the risk of error in the assembly.

The cost issue is a big factor when it comes to investments in production equipment in general. Respondent 2 states that the methods and equipment needs to be profitable. Too expensive equipment in production will result in a product that is too expensive which in turn may lead to less orders. Quality assurance equipment is by that evaluated extra and investigated if there is a big need for the equipment. Poka Yoke equipment is a high level quality method that is used in order to stop the processes if errors occur which leads to less waste and less mistakes made in production. Poka yoke solutions is widely used but it comes with high costs for software. This is used in both high and low volume. For low volume, a bigger focus is put to secure well trained and experienced personnel on these kinds of assembly stations, which also are a measure taken to maintain quality in a more cost effective way than procuring a lot of equipment according to respondent 3 and 4. Respondent 4 says that even though budget for low volume production seems to be narrow, quality is still as important.

Regarding the flexibility matter, most equipment used (vision systems, Pick to light systems, robots, bar code and QR scanners, controlled nutrunners, and more) in production is reprogrammable which means it can be adjusted and adapted to changes in the product and process. However, this again leads to costs related to software and a too high cost for changes lower the flexibility of the equipment. Pick to light systems used to maintain a correct picking sequence, correct parts and right amount can easily be adjusted or mounted on other shelves for new parts or changes in sequence with a reprogrammable spybox. Special designed expensive hardware is not as flexible but inexpensive special designed hardware can be seen as flexible. Another factor for the flexibility is overdimensioning the equipment to also fit possible future needs. Overdimensioning can be seen as a necessary waste in order to get a long term solution.

5.2.6 Conclusions The conclusions from the interview analysis are found key aspects for improving quality assurance in low volume lines. • Common errors is errors in picking operations due to part variants in different product models. • Common error causes is instructions not properly followed due to habitude. • Quality assurance during production is critical to reduce the risk of sending bad quality products to customers that can damage the company identity but also critical to reduce waste in forms of scrap and rework. • Wishes for further improvement is better traceability in preassembled parts, automated quality assur- ance to reduce human error, analysis and visualization of data collected from connected tools. • Big cost factor in poka yoke devices is how much time that needs to be spent on software for the devices in order to connect to the other production IT-systems. • In low volume lines, highly skilled and experienced operators is needed to keep high quality.

41 6 Discussion

In the discussion section, the thesis work is discussed with regards to the work methods and project execu- tion and results: a critical review on the thesis work as a whole. Validity and Reliability, future work and recommendations on short and long term is further discussed.

6.1 Project Execution The project has been conducted at Scania department of transmission assembly, DTTGP department of Product Introduction and E-mobility Projects. The master thesis goal and objectives was to evaluate to- day’s methods, equipment and processes for how quality assurance are handled and can be implemented in low-volume assembly line at Scania. The approach of the thesis has been of an inductive qualitative research approach with the aim to investigate how other companies and facilities are working with quality assurance. Through study visits, observations and interviews, the results of those has then been evaluated. The project scope and description from the start has been wide and flexible which allowed the possibility to take different paths to accomplish the thesis goals. The width and flexibility has been both positive and an obstacle for the project. Obstacles has been to sometimes hard to lay focus on the right path due to the wide range, but overall it has been educative and possible to follow the time and scheme for the project.

Many people has been involved in the thesis through different ways, from interviews, study visits and being in the same environment. The thesis has then been able to gathered ideas from different points of views and discussions with experienced employees. The project was performed by two students, which has been mostly advantageous. At the start of the thesis an advantage has been the possibility to discuss and share input and perspective of the subject. Another advantage of being two in the project is the support and dividing of the workload, the ability to take over each other and help. But also give each other space be able to focus on each task at a time. Disadvantage of the being two has been the time of decision making, sometimes decisions took unnecessary time to make due to some misunderstanding of each other and therefore required time to get on the same page. Overall the advantages has outweigh the disadvantages and the project has been smooth and possible to follow the plan and time scheme.

6.2 Validity and Reliability For the thesis gathering of data and the data has been a major importance and central of the project. The data gathered has been mostly qualitative. In the beginning a lot of effort has been put into analyze of the current state, analyze the deviations of the processes and discover which deviations has to be handled. Due to the circumstances of the current state being a new production line and had just recently started producing to customer’s order, the project lacked the necessary data of real deviations. In consultation with the supervisor of both LTU and Scania, the PFMEA document was decided to be investigated. This was necessary for the sorting and discovering of the deviations but the level of the validity and reliability is arguable. The reason is that the document has been conducted from start and are still live, many people has been working on it and used it. The structure and work done has not been consistent, sometimes there is only one person evaluating the PFMEA risks and also some changes has not always been updated. If the thesis would have been to specifically focus on the current state it would need more work to increase the validity and reliability of the data. Due to circumstances as mentioned the analyzed PFMEA was good enough to identify typical and general risks categories and the magnitude of those. But of course it would have been preferable and more valid to analyze real deviations and risks from customers.

Observations and interviews has both been very important method during the thesis. Observation is a major tool and has been used both during the study visits, and also internally at Scania. In both direct and interactive observation the observed person knew that they were being watched. This is both good and bad

42 for the validity, the bad side of it is the possibility of if someone know that they are being observed their performance could be affected and probably improve due to the cause. The good side is that they know the purpose of the work and also created good relationship to led to a sustainable attitude regarding observation and repeating work.

Interviews are also classified as a major tool in the thesis. The used method has been based of semi-structured interviews which is qualitative approach. All the answers of the interviews has been documented to be able to interpret and analyze the responds. To increase the validity of the interviews the type of the interviews has been focused on face to face dialogue. Some survey interviews has also been conducted afterwards for some causes to not misinterpret the documented interview. Every interviewed person has been chosen and picked by the authors in which assumed to be the most suitable for the subject, and not biased. The time between the first and the last respondent is relatively long, and therefore the knowledge of the authors had been increased between the time. This could also have affected the performance and analysis of the interviews. The last interview was recorded to increase the validity of the analysis of the respondent answers, and also made it easier to interpret and decrease misunderstanding and forgetting what the authors meant on the documentation. To increase overall validity every interview should have been recorded.

An important factor for the thesis is the reliability and for that has been to be clear with the subject and project. Every step of the work has been documented and explained in the thesis, making it possible to analyze how it was done.

6.3 Recommendations The recommendations for quality assurance in low volume assembly lines are according to the following sub- section. Short term recommendations are based on the current state. Long term recommendations are based on how to further develop and increase good quality for low volume assembly processes in general.

6.3.1 Short term Recommendations on a short term with regards to the current state assembly is according to the following points.

• Further securing picking operations on the transportation cart with numbered boxes, trays or compart- ments for dividing different parts making sure that the parts is secured on the cart during transportation from shelves to the work station for reducing risks of small parts getting lost or mixed up, and also reduces risks of waste in form of rework in picking operations. • Installing P2L equipment on critical parts connected to the nutrunners, to secure right part picked due to variants of parts and parts with similar appearance and parts that is critical to the function, life and safety of the product. • Further develop the live checklist used to secure remaining risks and new risks that come up during the assembly work overtime in the wait of other measure. By further describing the activities on the list, what assembly block it concerns to and what part number it contains to. Further, the checklist can be digitalized and put on a tablet or monitor by the assembly work station. In addition, a P2L lamp or button for the checklist can be added to ensure that the checklist has been read which function as a ”Right from me” signature when used.

43 6.3.2 Long term Long term recommendations for quality assurance in low volume assembly lines, in new assembly line projects, is to make space for quality assurance in budget. For quality assurance equipment a budget should be put from project start to proactive eliminate and minimize the discovered deviations. This budget contains infrastructure for connectivity between equipment and tools used, for critical parts pick and place operations can be secured with P2L to secure picking operations, connected nutrunners to secure placing operations along with digitalized live checklists. With all this in place and if it seem necessary, additional presence sensor equipment, specially designed for the specific purpose, can be added to a very small cost. It is also recommended to continue to use highly skilled and experienced assembly professionals, it is needed in low volume production due to the many activities, parts and equipment used. Securing quality in production needs to be prioritized for e-mobility products when these products are highly connected to Scanias future as a provider of sustainable transportation solutions. With the right priorities, and quality equipment in budget from the start, this can be achieved. Further, organizational cooperation between internal Scania plants should be put up in order to further improve quality assurance knowledge and methodology in the use of equipment to secure quality in the assembly process.

44 7 Conclusion

The conclusion section holds the found answers to the research questions which summarizes the master thesis work. The section also contain comments on the target fulfillment of the project.

7.1 Research Questions The thesis three research questions will be answered as following. • Which quality assurance methods and equipment exist on the market? Existing quality assurance equipment on the market that are used in the industry are identified as, connected nutrunners, vision systems, smart vision cameras, bar and QR code scanners, laser pointer guidance, different Pick to (Light/Voice/Vision/Tablet) equipment, presence sensor equipment, indus- trial robots, check lists and more. For further description of the identified equipment see the Results of Study Visit subsection 5.1. What can also be concluded is that many equipment are specially designed to fit the individual purpose.

• Which quality assurance methods and equipment are suitable for Scania’s low-volume processes in terms of cost, quality and flexibility? Based on pros and cons that has been analyzed in Analysis Study Visits 5.1.6. The equipment suitable for Scanias low-volume processes is P2L to secure picking operations, connected nutrunners and check- lists to secure placing operations. This is well used and common equipment all over the industry, with the flexibility in reprogrammable sequences for possible future changes and with respect to other pos- sible equipment cost wise in the approximated lower price range. In addition to further secure different placing operations, presence sensor applications can be special designed and added in the process to a small cost. • How can the suggested methods and equipment be implemented in Scania’s low-volume processes? P2L can be implemented at every part that is critical to the consequence for the end customer in terms of functionality, life or safety of the product. Placing operations can be secured together with connected nutrunner with the programmed sequence that will be blocked if the sequence is not kept to standard. In addition, other sensor application equipment connected to the sequence can be used to secure parts that is not associated with tightening operations. For more critical possible errors, a checklist should be used connected to a P2L lamp or button as ”Right from me” signature. Depending on the specific individual quality risks, special designed process descriptions for the earlier mentioned equipment and application.

In general, to connect different tools and equipment, an infrastructure needs to be developed and installed. Infrastructure that can watch over and keep track of the assembly sequences and equipment’s activity. This is a big cost factor, due to software development costs.

7.2 Target fulfillment The objective for this master thesis was to investigate what kinds of equipment for securing quality in assembly there is on the market, what equipment and how it can be implemented in Scanias low-volume assembly of electrified transmission and powertrain. This was achieved through qualitative research by study visits and observations of other production plants along with interviews of production engineering professionals. By have answered the research questions, fulfilled the requirements and given suggestions within the timeline. The master thesis projected is thus considered to have fulfilled its purpose and aim.

45 References

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46 Appendices

Appendix A Gantt Chart

i Appendix B Interview Guideline

ii