Development of production layout
A proposal of Lean model for a manufacturing company by using Value Stream Mapping
Framtagning av produktionslayout
Ett förslag på Lean-modell för ett tillverkningsföretag genom användning av värdeflödesanalys
Josefin Fransson
Faculty for health, science- and technology
Degree Project for Bachelor of Science in Mechanical Engineering 15 ECTS Credits
Supervisor: Abdulbaset Mussa Examiner: Jens Bergström Date: 2020-07-08
Serial number: 2
PREFACE
This Degree Project for Bachelor of Science in Mechanical Engineering will finish my three years of studies at Karlstad University before I leave for a Master’s program in another city in Sweden. I would like to bring attention to thank my supervisor Abdulbaset at Karlstad University for having patience with all my questions during the course of work. Also, thanks to Emma, Christina, and Leo at the Department of Engineering Science and Physics at Karlstad University for providing me valuable advice during the entire project. Last but not least, I would like to thank the persons at the company where the thesis was written for giving me the opportunity to perform this work.
The Degree Project for Bachelor of Science in Mechanical Engineering gained my knowledge and inspired me to continue to work with Lean and production-oriented tasks in the future.
ABSTRACT
A general aim among manufacturing companies is to create a high value for the customer by using few resources and gain profit as a result. Tools and methods from Lean can be used for streamlining the production in order to achieve a resource-effective, flexible, and fast production process. An earlier study has shown that productivity increased by 37% when Lean tools were applied. The aim of Lean is to have a continuous value stream by eliminating waste that does not add any value to the customer. The value stream refers to the processing steps a product passes through from the moment a customer places an order until the finished product whose purpose is being fulfilled. Waste in terms of transportation, inventory, wait, defects in products, and more impairs the flow efficiency. The choice of production layout has an impact on the grade of flow efficiency. Making a suitable placement of machines, inventory areas, shipment positions, and workstations can minimize the number of waste occurrences hence benefit a continuous value stream.
The purpose of this study is to design a suitable layout for a newly started manufacturing company.
The company does not have a current production facility as its enterprise development is in the start-up phase. The layout is designed for the future production facility that is under planning. The goal is to design a layout with minimal waste occurrences that benefit a continuous value stream.
The study is based on literature and data collections. The literature studies include Lean and
production systems as the main field. Relevant data were collected through interviews and study visits at similar manufacturing companies around Värmland. The value stream regarding the company will be described through a visual map. This is done by using value stream mapping as a tool from Lean.
Various layouts that are considered to be in alignment with the value stream will be designed and discussed. One of these layouts is chosen as being the most appropriate.
The results presented a layout and a value stream map with regard to the company’s production process. These were based on a predictable volume of two similar products that were expected to be sold during the first production year. Three scenarios of different production schemes with regard to the presented layout was presented. One production schemed was proved to be the most
resource-efficient. This was proved by calculations of machine capacity, the timeframe for
production, and customer request. Furthermore, a value stream map of a future workshop and business state was presented. The value stream map provided a comprehensive control over the value stream.
However, some data could not be provided. The starting point of this was considered to be unique as there was no current value stream to analyze or judge. Several assumptions, estimations, and
simplifications for a future state were, therefore, taken. The presented conclusion of the study was that the layout was designed according to the required manufacturing processing steps. Waste risks were assumed to be low in the presented layout due to a suitable placement of machines, inventory areas, and workstations. Space, material handling, and transportations were being held low hence benefit a continuous value stream. The layout was assumed to be in alignment with the value stream.
Recommendations for future work were to make simulations of different layouts before any implementations take place. The value stream map was obtained for future work in order to distinguish value-added and non-value-added activities by adding process data.
SAMMANFATTNING
Ett generellt mål för tillverkningsföretag är att på ett effektivt sätt skapa ett högt värde för kunden med få resurser. Detta för att generera vinst i företaget. Verktyg och metoder från Lean kan användas för att effektivisera produktionen och på så vis gynna en resurseffektiv, flexibel och snabb
produktionsprocess. En tidigare studie har visat att produktiviteten kan öka med 37% med hjälp av Leanverktyg. Målet med Lean är att skapa ett kontinuerligt värdeflöde genom att eliminera slöserier som inte bidrar med något värde till kunden. Värdeflödet avser den väg av förädlingssteg som en produkt genomgår från det att en kund lägger en beställning fram tills att det är en färdig produkt vars ändamål uppfylls. Slöserier i form transport, lager, väntan, defekta produkter och mer försämrar flödets effektivitet. Valet av produktionslayout spelar roll då den är relaterad till graden av
flödeseffektivitet. Genom att göra en lämplig placering av maskiner, lagerområden, lastplatser och arbetsstationer kan slöserier minimeras för att på så sätt gynna ett kontinuerligt värdeflöde.
Syftet med denna studie är att designa en lämplig layout åt ett nystartat tillverkningsföretag. Företaget som layouten designas för har inte någon nuvarande produktionsanläggning då de befinner sig i start-up fasen av deras karriär. Layouten designas åt den framtida produktionsanläggningen som är under planering. Målet är att designa en layout som gynnar ett kontinuerligt flöde för att reducera antalet slöserier.
Studien baseras på litteraturstudier och datainsamlingar. Litteraturstudien innefattar Lean och produktionssystem som huvudområde. Insamling av relevant data skedde i form av intervjuer och studiebesök på liknande tillverkningsföretag runt om i Värmland. Genom värdeflödesanalys som verktyg från Lean kommer en visuell karta presenteras för att beskriva värdeflödet inom företagets anläggning. Olika layouter som anses vara i linje med värdeflödet designas och diskuteras varav en utses som mest lämplig.
I resultaten presenterades en layout och värdeflödeskarta med hänvisning på företagets
produktionsprocess. Detta baserades på en preliminär produktionsvolym av två snarlika produkter som förväntades bli sålda under det första produktionsåret. Med avseende på den layout som valts presenteras tre olika scenarier av produktionsupplägg. Genom beräkningar av maskinkapacitet, tidsram för produktion och kundförfrågan visade sig ett produktionsupplägg vara mest resurseffektiv.
Vidare presenterades en värdeflödeskarta över ett önskat framtida läge som gav en övergripande kontroll över värdeflödet. Dock fanns en bristande tillgång på data. Utgångspunkten i denna studie ansågs därför vara unik eftersom något existerande värdeflöde inte fanns att analysera eller döma. Ett flertal förenklingar, avrundningar och antaganden gjordes. De slutsatser som presenterades av studien var att layouten var designad i enlighet med tillverkningsprocessen. Riskerna för slöseri antogs vara låga i den presenterade layouten på grund av en lämplig placering av maksiner, lagerområden och arbetsstationer. Utrymme, materialhantering och transporter hölls låga. Layouten antogs vara i linje med värdeflödet och därmed gynnas ett kontinuerligt flöde. För vidare arbete rekommenderas en simulering för att utvärdera olika layouter innan implementering. Värdeflödeskartan erhölls som grund för att vidare arbete för att addera processdata och skilja på icke-och värdeskapande aktiviteter.
PREFACE 3
ABSTRACT 5
SAMMANFATTNING 7
VOCABULARY 11
1. INTRODUCTION 12
1.1 Background 12
1.2 Problem formulation 13
1.3 Purpose and goals 14
1.4 Limitations 14
2. METHODOLOGY 15
2.1 Approach 15
2.2 Literature studies 16
2.3 Data collection 16
2.4 Thesis research methods 17
3. THEORY 17
3.1 Toyota Production System 17
3.2 What is Lean? 20
3.3 Lean Production 21
3.4 Value Stream Mapping (VSM) - A tool within Lean Production 22
3.4.1 Steps for Value Stream Mapping 22
3.4.2 Process data and calculations 25
3.4.3 Value Stream Mapping Icons 26
3.5 Facility layout 26
3.6 Production process 28
3.7 Basic layouts 29
3.7.1 Product/assembly-line layout 29
3.7.2 Process layout 29
3.7.3 Fixed-position layout 30
3.7.4 Cellular layout 30
3.8 Bottleneck 30
3.9 Lean production and layout 31
4. RESULTS 31
4.1 Description of the current state 31
4.2 Production request 32
4.3 Raw material and machines 33
4.3.1 Scenario 1 40
4.3.2 Scenario 2 41
4.3.3 Scenario 3 41
4.4 Production layout 42
4.5 Value Stream Map 44
5. DISCUSSION 44
6. CONCLUSIONS AND RECOMMENDATIONS 46
6.1 Future work 47
7. REFERENCES 47
8. APPENDICES 50
8.1 Appendix A - Grant project planning 50
8.2 Appendix B - Chosen layout proposal 52
8.3 Appendix C - Layout proposal 54
8.4 Appendix D - Layout proposal 56
8.5 Appendix E - Expanded production, layout proposal 57
8.6 Appendix F - Value Stream Map 58
VOCABULARY
Value stream: Sequences of activities a product passes through from the moment a customer places an order until it is a finished product.
Value Stream Mapping (VSM): A tool within Lean.
Waste: Activities that do not contribute to any value, non-value-adding activities.
Throughput: The time passed to get a product through the entire production process.
Flow efficiency: The total time for the value-added activities in the value stream in relation to the total throughput time.
Lead time: The time between the start of a process (putting an order) until the end when its purpose is being fulfilled (the product can be used by the customer).
Beams: Refers to the product used for interior walls, concerning construction manufacturers.
Rods: Refers to the product used for bed frames, concerning bed manufacturers.
1. INTRODUCTION
This chapter will present the background of the study, the problem formulation, its purpose, and limitations. First, the background provides a general description of manufacturing companies in general followed by an initiation to the company the thesis will be written for. Second, statements will be presented in which serve as a basis for the underlying problem formulation of the study. Lastly, the purpose and limitations will be presented.
1.1 Background
Having a continuous and effective flow of material and information is essential for achieving profit within industry organizations. A general aim among manufacturing companies is to create a higher value for the customer by streamlining the production. Transportations, machines, workstations, operators, and inventory are some of the many elements that must be arranged within a production facility [1]. A product’s pathway from the moment a customer places an order until it is a finished product, named value stream, consists of several coordinated activities. Hence waste in terms of time losses, transportation, inventory, and material waste can be found within the value stream due to the many operations and steps. As a result, businesses implement methods to develop an effective and flexible production process with minimal waste and maximum value [2]. Commonly, methods from Lean are applied for eliminating waste in order to optimize the performance in terms of quality, costs, and time [1]. Lean is a global concept that is used among manufacturing companies for streamlining the different areas and processes that exist within a facility. The core concept of Lean is to develop an effective and flexible process with minimal waste and maximum value [2].
“Lean is a way of seeing, operating and managing a business based on resource-efficient, flexible and fast processes that are driven by customers' current demand” translated from” [1, p. 11]
The manufacturing company the thesis is written for, started in 2016, has developed a beam based on paper as raw material by using a unique manufacturing technique. Their product is patented in Sweden and can be used for several applications where a strong and light material is required, but with less climate impact and for a reduced cost. One application for the company’s paper beam is for interior walls where steel as a material is regularly used today. Steel beams are ungainly and heavy for the worker, become sharp after cutting, and have a greater cost compared to the company’s paper beam. A life cycle analysis done at Karlstad University showed that the manufacturing of one steel beam generates the same amount of CO2emissions as 14 paper beams from the company. The manufacture of the paper beam is based on physics and chemistry. It passes through a number of process steps before it is a finished product. Firstly, a big roll of paper comes in as raw material that becomes processed in a rewinding machine into smaller rolls into a certain width. Secondly, the processed paper rolls are placed in the main machine where the paper is being transformed into the product. The process in the main machine consists of several subprocesses that are performed automatically driven after each other. The paper is rolled out and dipped into a special adhesive and smoothed to obtain the correct amount on the paper’s surface. When entering the machine, the paper is wrapped around a solid core at a certain speed and tension, in the correct number of layers. As a last step in the main machine, it is cut to the desired length by means of roller shears. Lastly, the paper
beam has a certain drying time depending on its size (e.g. profile dimension and length) in order for the adhesive to solidify completely until it is a finished product and can be dispatched for sale. [3].
However, the company has no existing production facility today since they are in the start-up phase of their career. Their first market target is to produce two profile dimensions of the product. Beams for the construction industry and bed rods for bed manufacturers. Right now, quality tests are in progress to certify the product to enter the two markets. The prototype parts used for the quality tests are manufactured from a supplier that is based in Germany.
Previous research has verified that manufacturing companies can increase their industrial competitiveness by having an effective value stream. The choice of the facility layout is strongly connected to the grade of effectiveness in the value stream. Applying methods from Lean when conducting a facility layout benefits the value stream and can increase productivity. An earlier study has shown that productivity can increase with as much as 37% when Lean tools were applied [4].
Planning and scheduling a suitable facility layout that is in alignment with the flow of material is an important contributor to achieving productivity. Planning a layout includes making an optimal placement anything needed within the facility such as machines, inventory, and workstations to reduce possible waste [5,6].
“Facility layout has being a significant contributor to manufacturing performance, has been studied many times over the past decades. (Tompkins et al 1996) was concluding that a good placement of facilities will contribute
to the overall efficiency of operation and can reduce until 50% of the total operating expenses. (There, 1964) also state that the good placement of facilities will reduce about 20% to 50% of the total operating expenses in
term of reduction costs by 10% to 30% annually in material handling costs in manufacturing industry.”
[6, p.261]
The procedure of how raw material comes into being a finished product includes the relationship between machines, material, and workers. Using Value Stream Mapping (VSM) as a method from Lean provides a comprehensive view of the entire process within the facility. A value stream map is a visual description that reflects the physical flow of material, products, and customers [1]. It benefits productivity and effectiveness since waste can be identified and reduced. As a result, the lead time can be shortened by 50% and the time regarding material handling can be reduced [7].
1.2 Problem formulation
Having a suitable facility layout for manufacturing companies is crucial for achieving profit by having an effective value stream and thus increase the throughput (i.e. the amount produced). Depending on volume and product variety, a decent production facility is conducted by making the most convenient placement of machines, inventory areas, workstations, and shipment position [6]. Waste such as transportations, time, motion, and material handling can be either reduced or entirely eliminated by optimizing the facility layout [8]. Based on these statements, the following problem formulation is presented:
How should the future facility layout for the manufacturing company be designed based on an optimal layout to achieve an efficient value stream?
1.3 Purpose and goals
The purpose of this thesis is to examine what aspects manufacturing companies need to take into account in the planning of a production facility. The thesis will investigate how a production layout should be designed in order to achieve a continuous value stream. The goal is to:
● Develop a suitable layout that is in alignment with the value stream.
● Design a layout that requires minimal space, time for material handling, and transportation routes.
This will be done with regard to Lean with its tools and methods as a foundation for creating the best possible condition for the future production facility. A layout will be presented to define how the tangible fixed assets can be designed in the most suitable way in alignment with the value stream. In addition, Value Stream Mapping (VSM) as a tool from Lean will be performed for identifying, prioritizing, and eliminating the waste risks in the value stream [9]. A value stream map of a future state with the best guess will be presented.
1.4 Limitations
The study is being limited to a layout that will manage one volume of two products. These products require the same type of manufacturing technique. The production facility that the layout will be designed for is under planning as no physical facility exists yet. Several assumptions, estimations, and simplifications for a future state will, therefore, be taken. Focusing on details regarding the production will be too extensive for this study. Furthermore, value stream mapping is usually made up by
analyzing a current state in order to make improvements for a future state [9]. In this study, there is no current state to analyze. The value stream map will present a future state with the best guess. Further limitations are:
● A value stream includes all activities a product passes through from the moment a customer places an order until it is a finished product. The value stream will be limited through the facility in this study, see figure 1.
● The layout is based on a predicted volume that will be produced during the first production year.
● The layout will not provide any detailed specifications
● Some data can not be provided in the value stream map
Figure 1: Limitations, modified from [2], with permission.
2. METHODOLOGY
This chapter provides a presentation of how the study was conducted. A comprehensive approach will be described followed by more specific details about literary studies, gathering of data and
information, and the thesis research method. In addition, qualitative and quantitative research methods will be highlighted.
2.1 Approach
The study started with an initiation meeting with the company the thesis was written for. The study’s purpose and problem formulation were defined after some discussion and guidance with the
supervisor at Karlstad University and the company. Thereafter, the literature study started in order to obtain a fundamental understanding of Lean production, facility layout, and the Lean tool value stream mapping. The literature studies came to create a wide theoretical background. The theoretical background served as a basis for the rest of the performed activities during the entire work.
The literature study was ongoing in parallel with report writing, study visits, and interviews. Mainly chapters one, three, and parts of chapter two were written in the report in parallel with the literature study. The work with developing the requested layout began when the theory chapter in the report was completed. Various layouts were designed and drafted. This was done by using paper and pen and by using the software Lucidchart. The layouts relied on the obtained theoretical background from the previous literature study together with calculations of data that were given from the company. Three different layouts were presented to the company in which one of them was chosen. It was considered obvious during the presentation meeting that one of the three layouts were most suitable according to the request. However, it led to some discussion since all of the three layouts came with their own advantages and disadvantages. The work with conducting a value stream map as the final activity started once the layout had been chosen. The value stream map was performed by making further calculations of the given data. Some estimations were done since the value stream map presented a future state with the best guess. Maintaining work with writing chapters four, five, and six in the report was ongoing in parallel.
Furthermore, continuous contact with the supervisor at the university and the company were held during the entire work. The contact was mainly held through physical meetings and emails. In addition, meetings with a teacher from the Department of Engineering Science and Physics at
Karlstad University regarding value stream mapping were held. Three meetings about value stream mapping took place during the end of the work since it was the last activity.
2.2 Literature studies
The literature studies started with searching for information about the history of Lean to gain
fundamental knowledge. The intention was to discover where it came from and why it has been such a well-known approach to rely on within manufacturing industries for many years. A strong suggestion from several professionals at Karlstad University was to start with reading the book “The Toyota Way” by Jeffrey K Liker. The book came to serve as a basis when searching for further relevant literature and previous research about how production layout is related to Lean and value stream mapping. The information searching took place through Karlstad university’s database “Onesearch”
by mainly using the keywords; Lean, Lean production, production system, production layout, value stream, and value stream mapping. The keywords regarding layout were also used on the platform ResearchGate when searching for previous research within the subject. The used information comes from books and articles of previous research. The supervisor and other professionals at the
Department of Engineering Science and Physics at Karlstad University have advised about relevant literature and articles.
2.3 Data collection
Interviews with the supervisor at the company were held in order to understand the production process. Several interviews took place since the need for more information about the production process emerged in parallel with the work in progress. Properties of the raw material and machines were collected and noted during the interviews. Besides interviews, the manufacturing process was observed through a recorded video of the main machine where the product is generated. The movie was recorded by the supervisor at the company during a visit to Germany where the main machine is currently being located. The supervisor at the company did also contribute with knowledge from previous experience that increased the understanding regarding manufacturing and production in general.
Study visits at OptiPack, Vestre, and Volvo were made. All companies are within the manufacturing industry whereas OptiPack and Vestre are small manufacturing companies similar to the company the thesis was written for. The aim of the study visits at OptiPack and Vestre was to gain an
understanding of how different layouts can be designed and how it affects the flow of material.
Whereas the aim of the study visit at Volvo was to gain knowledge about how value stream mapping is used and why it is a good tool within Lean. All three companies adapt to Lean production in
different grades. The study visit at OptiPack AB in Sunne provided a view of a bad layout as it did not follow the flow of material. The disorganized layout design caused many internal transportations and intermediate storage between the process steps. The persons at the OptiPack were well conscious about their bad layout and expressed that they need to change it for performing more efficiently. In contrast to OptiPack, the study visit at Vestre Production AB in Torsby provided a view of a good layout. Their layout was well considerate as it followed the flow of material. Internal transportations and intermediate storage between the process steps were held low because of the suitable layout. The visit to Volvo in Arvika took place after meeting the company at the job fair Hotspot at Karlstad university. Volvo provided a presentation during the visit to Arvika regarding how they adapt to Lean
methodologies. The presentation was mainly about how they are working actively with value stream mapping. This gave a deeper understanding of how the Lean tool is put into practice and why it is a valuable tool for streamlining production.
2.4 Thesis research methods
Two different approaches are usually distinguished within methodology; qualitative and quantitative research. The characteristics of the two approaches differ. Qualitative research aims to create a deeper understanding of the objective. The purpose is to understand a context in terms of why and how. The data collection methods in qualitative research are usually made up of interviews, observations, and/or discussions. The collected data are textual. In contrast to qualitative research, quantitative research aims at previous research based on existing theories. The purpose is to quantify a problem by answering how much, how often, or finding correlated variables. The data collection methods in quantitative research can be questionnaires, opinion surveys, and/or exit interviews. The collected data are statistical data. [10, p. 41].
The thesis research method concerning this study is mainly qualitative. However, all requirements for a qualitative method are not fulfilled. There are some factors of quantitative elements combined.
3. THEORY
This chapter examines the literature which has been applied and served as a foundation for the thesis.
Existing theories and philosophies will be presented in order to gain knowledge about Lean
production. The theory will review general practices within production and why it is useful to rely on Lean when conducting a production layout. Furthermore, the Lean-tool Value Stream Mapping will be presented.
3.1 Toyota Production System
The aim of this section is to shed some light on the Toyota Production System (TPS) in order to understand the theory behind Lean and its tools. TPS is the framework that formed and advanced Lean, which will be addressed in the next section
Toyota has been recognized for being the fastest in the world when it comes to product development.
They are considered as being the leader in the manufacturing industry in terms of quality,
productivity, manufacturing speed, and flexibility. The author of the book The Toyota Way, Jeffrey K. Liker, explains the leadership methods, the ways of thinking, and the philosophy that underpins Toyota's success. Liker provides a comprehensive description of the tools and methods that are included in the Toyota Production System and how its principles establish Toyota's culture with the key concepts "continuous improvement" and "respect for people" [11]. The Japanese word kaizen is a central concept that is used when the Toyota Production System is put in a context where kai means and zen means good [12]. The two merged words, kaizen, stands for continuous improvement which characterizes Toyotas’ fundamental attitude [11].
The general control of Toyota together with the tools and methods included in the Toyota Production System is based on 14 principles distinguished into four main areas; philosophy, processes, employees and partners, problem-solving. The principles were identified by Liker during his research work. A description of the 14 principles together with its division into the associated main areas is presented in the following text. [11].
Philosophy
1. Long-term philosophy.
The company should always stay true to the long-term philosophy by making decisions based on it, even if it might have a negative effect on the business in the near future. Working towards a common goal and develop by making the right decisions in terms of the company, employees, and customer is more important than making money. The value should be provided to the society not only to the customer. This principle is the philosophical starting point and the foundation of all other principles.
Processes
2. Continuous process flow.
Arrange processes to obtain the highest quality with the shortest possible delivery time and lowest cost. Activities that do not add any value should be eliminated to the maximum extent possible. The goal is to transform waste into value by having a continuous flow. Having good communication between activities and people is essential to detect defects and predict errors.
3. Avoid overproduction.
Produce according to customers’ demand - at the right time, in the right quantity. Based on Just-In-Time (JIT) where you let the customer's demand control the production to eliminate
unnecessary inventory space. A “pull” system is achieved once Just-In-Time is implemented to avoid overproduction. Smaller batches provide better control of the quality thus identifies mistakes faster.
4. Equalize workload (Heijunka).
Employees should not have too high a workload, it should be distributed as well as the production.
Heijunka comes from Japanese and the core idea is about creating a uniform product sequence. It is better to build a stock of finished products and not produce according to customer demand as it can vary greatly. Variation can be reduced by dividing production by volume and production mix.
5. Integrate quality.
Use assurance methods to integrate quality into the product to prevent inaccuracies. The Japanese word, Jidoka, is about using human intelligence in combination with equipment. Having a system that notifies directly when something is wrong prevents problems in later steps, which in turn generates less unnecessary rework.
6. Continuous improvement and employee engagement.
High production efficiency in combination with high quality can be maintained if standardized work is followed and if there is information available. Employees should have the right to have opinions
and share them. Improvement suggestions from employees should be encouraged. Good suggestions can be implemented and standardized throughout the entire organization.
7. Visualization.
A structured work environment through visual descriptions such as symbols, marks on the floor, or signals benefits a standardized way of working. It should be obvious through the visual when working.
8. Technology.
People should not be replaced by technology. New technology can contribute to great improvement and should be encouraged, but to be taken with caution. It is important to test the technology properly before implementing it. The aim is to make use of technology as a tool in order to facilitate the employees' work.
Employees and partners
9. Leaders.
The task of a leader is not just to perform tasks or to distribute them. A leader represents the company's philosophy and should, therefore, be a role model for the employees. Expertise can be found within the company, it should be used rather than searching for answers from external sources.
10. Teamworking.
Encourage people within the company to collaborate and achieve improvement by solving problems together. Working towards a common goal creates a stable culture with clear values to aim and strive for.
11. Partners and suppliers.
Form a company that supports others by sharing knowledge for mutual long-term advantages. Guide subcontractors to reach goals and challenge them to develop.
Problem-solving
12. Question problems.
Create a full understanding of a problem-situation by questioning. Questions should be encouraged no matter what position you are. Defects that have arisen can be deduced from the production back to the purchasing stage by questioning.
13. Make decisions.
It is essential to consider different kinds of alternatives when making a decision. Persons that will be influenced by a new decision should be allowed to participate in decision-making.
14. Continuous improvement.
A mistake should be considered as an opportunity to learn rather than a failure. Repair problems by finding the cause. Finding the fundamental cause of a mistake creates possibilities that can be discovered.
The principles are guidelines that represent how an organization should be conducted according to Toyota’s values. Including all levels throughout the organization and striving for a common goal is the foundation for prosperity. Toyota Production System is usually illustrated in a house, titled TPS-house, where the principles, tools, and methods are integrated. The house, according to figure 2, is a structured framework where each part of the house (e.g. roof, pillars, and ground) is essential for the organization to act together as a whole [11].
Figure 2. The TPS house modified from [11].
3.2 What is Lean?
The Lean concept as in Lean production, Lean management or Lean manufacturing is an approach or strategy of how an organization should be conducted. The aim is to achieve profitability by being flexible and productive. Lean emphasizes the quest to eliminate everything that does not add value for the customer by focusing on the flow efficiency. The flow efficiency is defined by the total time for the value-added activities in the value stream in relation to the total throughput time [6]. Lean addresses a number of strategies and methods that can be used to efficiently analyze existing
resources and question its appropriateness. The core purpose is to achieve an efficient and continuous flow in alignment with the customer’s needs by eliminating unnecessary resources through the entire value stream (i.e. from raw material to final product) [1].
Lean is an extension of Toyota's production system and got its base from the principles pioneered by the Toyota Production System. The knowledge about Japanese quality thinking began to spread and became globally acquainted when the world's industries encountered financial challenges due to the oil crisis in the 1970s. Toyota managed the crisis noticeably better with higher profits than its competitors. On behalf of the Western European and North American automobile industry in 1979, researchers from the Massachusetts Institute of Technology got to examine Toyota's profitable way of working. They studied the background behind Toyotas’ succession for five years and interpreted Toyota's way of working according to the Toyota Production System model. Massachusetts Institute of Technology coined the term “Lean production” in association with the publication of the book
“The Machine That Changed The World” as a result of the five years of studies [13]. The founder of TPS, Taiichi Ohno, expressed himself in 1988 about Toyota's way of working and how it created value:
“All we are doing is looking at the timeline from the moment the customer gives us an order to the point when we collect the cash. And we are reducing that timeline by removing non-value-added wastes” [11, p. 25]
However, Lean is more than maximizing the value to the customer while minimizing the amount of waste (e.g. human effort, equipment, time, space). According to the 14 principles mentioned in section 1.1, Lean includes focusing on engaging and develop people. It is integrated into continuous learning, quality, and improvement work. Teamwork and supportive leadership that encourages the team members and is essential to successfully achieve Lean. Therefore, Lean is not something that can be easily implemented. It requires visions to work against in order to cover the entire organization as it occurs at the time in which the business is capable to adapt the Lean mentality [1,14].
3.3 Lean Production
When Lean production or Lean manufacturing is put in the context, muda, is associated as a central concept. Muda stands for waste in Japanese and aims at obstacles that cause interruptions in the flow.
7+1 wastes were identified by Liker, mentioned in section 1.1, are activities and actions that do not contribute to any value to the product or service. Reducing these 7+1 wastes benefits the value stream and improve a continuous flow in terms of effectiveness and productivity. In addition, it can also eliminate risks associated with the activities [11]. The wastes that were identified by Liker are principal elements to focus on within Lean production to achieve a high flow efficiency and increase profitability. Briefly, the aim is to convert muda into value by doing more with less - less human effort, less equipment, less time, and less space [13]. The 7+1 wastes that were identified by Liker are:
1. Overproduction: Manufacture too much, early, and for safety.
2. Wait: Ineffective value stream because of obstacles.
3. Transport: Internal transportation routes within the facility.
4. Processing: Doing more than the customer requires.
5. Inventory: Store more than what is needed.
6. Motion: Movement for the employees to perform their tasks.
7. Defects in products: Unnecessary rework.
8. Non-utilized creativity to the employees: Taking advantage of employees' knowledge, one of the foundations of Lean.
There are a number of Lean tools that can be used to identify waste in order to optimize performance and improve productivity. Commonly used Lean tools are Value Stream Mapping (VSM),
Just-In-Time (JIT), kanban, Single Minute Exchange Dies (SMED), and more [1].
3.4 Value Stream Mapping (VSM) - A tool within Lean Production
Value Stream Mapping is a tool from Lean that provides a way to describe what different processes and activities a product passes through before it reaches the end-customer. It encompasses all the steps from raw material to the final product and covers the mapping, analysis, and design of value streams that exist within a facility. It is a good approach to use for identifying what needs to be done by gaining control over the value stream. The foundation is made up of using “paper-and-pen” as it includes drawing a product’s path by hand. It is useful to physically walk in alignment with the different processes and observe them while taking notes. It provides a deeper understanding of the flow of material and information in the value stream. Depending on the situation and purpose, it is important to recognize what process data needs to be collected [2]. In this way, the lead time (i.e. the period of time between the placement of an order and the shipment) can be separated into
value-adding and non-value adding activities. As a result, it will benefit to a more efficient flow since non-value adding activities can be detected and, therefore, eliminated. The aim of using Value Stream Mapping as a tool from Lean is to improve flow efficiency by minimizing the amount of waste while maximizing the value. It is a useful method to apply for streamlining production since the concept is based on giving a comprehensive overview of the total process rather than on individual
sub-processes. It provides a highly visual description of the entire flow and serves as a basis for improvement. However, it can be used to describe sub-processes if desired and depending on the process’s complexity [2,9].
3.4.1 Steps for Value Stream Mapping
It is essential to identify a product family before start working with Value Stream Mapping. A product family is a collection of products that requires the same type of manufacturing technique and passes through similar processes within the facility. It should be easy to follow the product family's path along with the process steps and to write down the flow of material and information. However, the choice of product family does not obviously apply if the factory has one single product or one type of product family. If that is the case, the product's path can be followed as it is the only type with similar characteristics [1,2,9].
Figure 3: The steps for creating Value Stream Mapping, modified from [2].
According to figure 3, Value Stream Mapping consists of three steps in which are performed after the product family has been chosen. First, a map of the existing value stream is designed, called “current state”. The current state describes the actual flow of material and information within the facility. An example of a current state map shown in figure 4. Second, an analysis of the current state is made followed by drawing a new map of the desired future value stream, called “future state”. Principles from Lean can be, if necessary, integrated into the future state map for improvements. An example of a future state map is shown in figure 5. Third and last, a work plan for implementing and realizing the future state is made. The third and last step usually takes the longest time since it is where the
practical change will be carried out [2,9].
Figure 4: Current state map [15], with permission.
Figure 5: Future state map [15], with permission.
3.4.2 Process data and calculations
The required process data that is added in a value stream map depends on the situation. It is important to identify what process data that is necessary and for what purpose [2,6,9]. A list of commonly useful process data and how they are calculated is presented in the list:
● Process time (P/T): The entire time for an item to pass through a process. It includes the time for preparation, running time, and the after treatment.
● Cycle time (C/T): The time for an item to be in the same state as the previous one.
● Uptime: The percentual relationship between operational machine time and the total available time.
● Set up time (S/T): The time taken to change from one activity to another.
● Takt time: The pace of producing units at a rate that meets customer demand
Takt time = Avalible working hours per day
(eq. 1-1) Quantity of output required per dayCycle time = P rocess time (eq. 1-2) Number of units produced
3.4.3 Value Stream Mapping Icons
Figure 6: Symbols with its meaning and use, modified from [2].
Value Stream Mapping is a quantitative method that provides a detailed description of how the resources are used in the existing facility. The map is represented in a standardized language by using visual symbols regarding customers, transportations, inventory, and more. The advantage of using symbols is that everyone should be able to understand through the visual without having previous knowledge [2].
3.5 Facility layout
A facility layout, also known as production layout, is an arrangement of everything that is needed within a facility to achieve desired production outcomes [6]. A layout composes the physical
placement of different elements such as transportations, machines, workstations, and inventory [16].
Decisions regarding location, process flow, floor layout, and material handling system must be taken into consideration in order to achieve a layout that ensures a smooth flow of material [6]. Having a layout in alignment with the flow of material is essential for performing efficiently and maximize productivity. However, it is important to point out that a production system usually contains more than just one flow of material. There is normally a number of different flows that need to be organized [5].
The principal structure of the layout is strongly dependent on what production system it is designed for. The manufacturing of the product may require repetitive operations in a certain sequence, special machines, or equipment. Volume and product variety are two core aspects that need to be taken into account and how they relate to the process type. Volume and product variety have a strong impact on the layout design and the grade of provided flexibility. The product can vary from custom specific products that are produced in a low volume to products that are produced in a high volume with low variety. The process type, volume, and the product’s variety are strongly connected to one and other.
The process types refer to how processes and activities are organized and can be categorized by a one-piece process, intermitted process, and continuous process. The relationship between volume, product variety, and process type can be determined in a product-process matrix, shown in figure 7.
The process type establishes the preconditions that apply regarding the layout in terms of design and flexibility. [16].
Figure 7: Product-process matrix showing the relationship between volume, product variety, and process type, modified from [16].
A one-piece process is characterized by producing unique items according to specific customer requirements, one by one. An intermittent process implies when each item is managed in intervals
according to the manufacturing order. The two subcategories of the intermittent process constitute a connected and non-connected flow. The difference between these two is the intermediate storage. The items are moved without intermediate storage in a connected flow whereas they are intermediately stored between process steps in the unconnected flow. A continuous process, which is the contrast to a one-piece process, is characterized where the same type of items with similar properties are
manufactured. The items requiring the same process steps are produced in a continuous flow without interruption from external changes. [16].
The relationship between the process types, volume, and product variety, shown in the
process-product matrix in figure 6, provides a measure of the process type appropriateness. Going outside the dashed diagonal line can lead to unnecessary costs by compensating for either low flexibility or for a process that has untapped flexibility. [16].
3.6 Production process
Regarding the company’s production process, no big changes take place whether beams for interior walls or rods for bed frames are being produced. The two products require the same type of
manufacturing technique including raw material and after treatment. The difference between the products is their profile dimension. The rods have a smaller cross-section compared to the beams.
A comprehensive description of the production process is presented through a flowchart diagram in figure 8. The figure is also attached for a detailed view, see appendix A.
Figure 8: The production process from raw material to the finished product described in a flowchart diagram.
3.7 Basic layouts
The fundamental structure of a layout differs in which it depends on what production system it is aimed for. Whether the layout supports the production of high volumes and many variants, different basic layouts can be distinguished and placed into four principal areas, see figure 9. [6,17].
Figure 9: Four basic production layouts.
However, beyond these four basic production layouts, a fifth can be categorized. A combination of these is also an option since each layout comes with its own benefits and detriments [8].
3.7.1 Product/assembly-line layout
A product layout, also known as assembly-line layout, is suitable when producing in large quantities or when the manufacturing technique is continuous. No big changes take place because of a basic standardized design. It involves performing repetitive tasks in a particular sequence. The various processing steps are organized in a line where the product determines how the various resources should be distributed. It is an advantageous layout since it provides a comprehensive view of the material as it flows in a line and the throughput time can be shortened. Usually, a conveyor is used to move the material forward between the processing steps at a regular interval of time. However, a mechanized moving platform makes the layout inflexible. It is difficult to change both the design and the different processes. In addition, a disruption or collapse of one machine within the line interrupts the entire production. The maintenance costs are, therefore, high in order to ensure a smooth flow of material [6,17].
3.7.2 Process layout
Unlike the product layout, the tasks are not performed in a particular sequence regarding the process layout. This layout is suitable when producing more custom specific products in smaller quantities as the different processing steps vary among different products. Items with similar processing operations can be grouped together and produced in batches. The process layout provides higher flexibility compared to the product layout since no fixed mechanized transport is being used. The movement of material between different machines is usually done manually by a truck. This facilitates making changes in design as well as in the processes. It also permits the machines to collapse to a greater
extent compared to the product layout. It does not interrupt the entire production since substitute machines are usually available for replacement. The maintenance costs are relatively low since low-cost machines for general purposes are more likely to be used. However, the grade of product variety requires more time effort for material handling. The layout provides a low output rate due to a more complex processing schedule for each product. The cost per unit is, therefore, higher [5,6].
3.7.3 Fixed-position layout
A fixed-position layout is appropriate when the product is large or too heavy to move (e.g., nuclear power plants, buildings, airplanes). The required tools, equipment, or material are brought by the worker to the product’s position as it remains in a fixed position. It is not possible to foresee the advantages or disadvantages of this layout. There are usually no other options when a fixed-position layout is needed due to the stationary types of products [6,17].
3.7.4 Cellular layout
The cellular layout includes collecting parts with similar characteristics, called part family, and gather them into groups according to production similarity. The production equipment is organized
according to production similarity. This serves as a basis for how machines and workstations are being organized within the facility. The group of products with similar characteristics are
manufactured in a cell of machines (i.e. machines that are grouped together). This saves floor space and provides better access for the workers due to a smaller distance between the different machines. A cellular layout provides good flexibility for the production of small batches. It is suitable for products with a medium variety [6,17].
3.8 Bottleneck
Regarding the choice of layout, it is important to consider the placement of the bottleneck since it has a significant impact on production efficiency [2]. A bottleneck is defined as the process operation with the most loaded resource or as a point in production where an operation surpasses the capacity. It is the narrowest point in the flow with reduced ability to produce units at the same rate as the other operations within the facility. Every production system has its own bottleneck that needs to be identified since it has an influence on flow efficiency and affects the total throughput time for the entire system. Hence, it is likewise the point where the production systems’ limitations are prescribed [18,19].
Figure 10: Illustration of a bottleneck and how it limits the flow within the production.
The bottleneck is identified by calculating what operation having the longest cycle time (i.e. the operation producing the least amount of unit per hour) [6]. Once the bottleneck is recognized, its placement needs to be considered in order to reduce its impact. A bottleneck occurrence at improper placement leads to unnecessary impairment of productivity. If a bottleneck is placed at the beginning of the flow, subsequent processes will be negatively affected hence increase the amount of non-value adding time due to queuing. It creates a situation with underutilized resources such as idle machines and inefficient operators that cannot perform their job properly. As a result, it increases production costs and lead time [18, 20].
3.9 Lean production and layout
Lean production has an impact on layout design as it supports a continuous value stream with minimal waste. Its methods and strategies facilitate the identification of possible waste and bottleneck
operations that increase the throughput time and impairs the use of production resources [4]. It supports a layout where the impact of the bottleneck process is held low to obtain a continuous flow through the entire facility [19]. Applying Lean production as a foundation when making decisions about how the different elements should be allocated benefits productivity. An optimal layout can minimize waste and improve flow efficiency [6]. A reduced distance between machines and
workstations provides the workers with better conditions to communicate and work more effectively.
Using the available floor space to its greatest extent reduces the number of transportation routes as well as the number of operations requiring transportation. As a result, it can shorten the lead time, reduce production costs, and improve the use of production resources [21].
4. RESULTS
The results chapter provides a description of the current state and preconditions provided for developing a proposal on production layout. A production request, data on properties of the raw material, and characteristics of the machines will be presented. Three different scenarios of production schemes will be provided. The scenarios are based on calculations of data given by the company the thesis was written for. A proposal layout is designed and a value stream map is performed. The result is based on the theory and calculations of the given data.
4.1 Description of the current state
The manufacturing company is in the startup phase of their business. Their products have not yet entered the market. Quality tests are currently underway to get required certificates before the business can begin. Their first market target is to enter the house construction business and furniture production where it is a great chance of selling large volumes. The company has identified two demanded products in these business areas; beams for interior walls and rods for bed frames.
However, there are several other applications where a strong and light material is required such as in traditional building, modular building, pallets, and packaging. The products that are used for the quality tests are currently being manufactured from a supplier in Germany where the main machine is located. The main machine is specially designed as the manufacturing technique of the products is based on physics and chemistry. Both beams and rods have a drying time of 4h after the main machine. The drying takes place on a 24 m long conveyor. The raw material consists of a special
adhesive and paper that comes from the Swedish forests. The paper comes in a big roll with a width of 2.4 m and a diameter of 1.0 m. The big roll is then being cut into 20 smaller rolls in a rewinding machine. The rewinding machine is located at Stora Enso Skoghall in Sweden. The small processed rolls are then shipped to Germany where they are being placed in the main machine.
In the meantime, while the quality tests are carried out, the company is raising capital through investors in order to start their own production facility. The future facility is planned to be located in Sweden. The whole production chain, from raw material to the end-product, will be managed within the facility without any external suppliers (i.e. both rewinding- and main machines will be provided).
A proposal of a suitable production layout is needed in order to get a perception of how much space is required for the future facility. The layout will serve as a basis when searching for existing facilities to rent.
4.2 Production request
The company has identified an estimated volume of the two demanded products, beams and rods, that will be sold during the first production year. One production year is equal to 45 weeks. The requested volume of the two products are:
● 14.6 million meter beam with the standard profile 45x70mm
● 5.0 million meter rod with the standard profile 14x67 mm
The volume of the two products is based on previous data gathered from its competitors within the same industry. The two products in its application are shown in Figures 11 and 12.
Figure 11: Beams for interior walls with its standard profile 45x70 mm.
Figure 12: Rods for bedframes its standard profile 14x67 mm.
However, the estimated volumes are highly preliminary. The future production layout must, therefore, be designed so that an expanded production can take place in a short amount of time. The demand is a production layout that is in alignment with the flow of material based on the predictable volumes. It should also provide good flexibility and use of the floor space to its greatest extent. Furthermore, the distance of internal transportations, as well as the number of transportation tours, should be kept low.
4.3 Raw material and machines
The raw material for manufacturing the products mainly consists of paper. There is also adhesive required but data on its properties were not provided. However, the adhesive is included in the calculations that will be presented, but its particular amount can not be specified.
Raw material - paper roll
Given parameters:
Paper mass /square meter = 0.175 kg/ m2 ø = 1.0 m
L = 2.4 m
= 2700 kg
mpaper roll
Figure 13: The raw material, paper roll.
Calculations
=
15 428.6 /paper roll (1) 2700 kg0.175 kg/ m2 m2
1 m*2.4 m*0,175 kg/ m2 = 0.42 kg/one m paper roll (2)
=
6430 m paper/roll (3) 2700 kg0.42 kg/m paper roll
Paper required for manufacturing the requested volume
Given the yearly volume of the two products, beams respectively rods, different amounts of paper will be required. This because of different profile dimensions and volume requests of the two products.
Beams
Given parameters:
Profile dimension = 45x70 mm Length = 3000 mm
Paper consumption = 2.07 m2paper/m beam Production request of beams: 14.6* 106 m
Figure 14: A simplified CAD-drawing of the beam.
Calculations
)* = 30.22* paper (4) 14.6 m beam
( * 106 2.07 m paper/ m beam2 106 m2 (1) and (4) gives:
≈1959 paper rolls/year (5) 30.22 10 m* 6 2
15 428.6 m /paper roll2
Rods
Given parameters:
Profile dimension = 14x67 mm Length = 890 mm
Paper consumption = 1.44 m2paper/m rod Production request of beams: 5.0* 106 m
Figure 15: A simplified CAD-drawing of the rod.
Calculations
)* = 7.2* paper (6) 5.0 m rod
( * 106 (1.44 m paper/ m rod)2 106 m2 (1) and (6) gives:
≈
467 paper rolls/year (7) 7.2 10 m* 6 215 428.6 m /paper roll2
Machines required for manufacturing the requested volume
Two machines, the rewinding- and main machine, are required for manufacturing the two products. In order to minimize the time regarding set up, two identical main machines will be obtained. One will mainly manufacture rods working 2-shift and the second machine will mainly manufacture beams working 5-shift. Furthermore, one rewinding machine working 5-shift will be obtained.
Rewinding machine
The big paper roll will be processed in the rewinding machine in order to obtain the correct width.
The roll will be cut into smaller rolls before it will be placed in the main machine. The same width is required regarding both beams and rods.
Given parameters:
ø = 1.0 m l = 0.120 m
= 95%
η
rewinding machine=
800 m/minv
rewinding machineFigure 16: The processed rolls after passing through the rewinding machine.
Calculations
= 20 rolls (8) 2.4 m
0.12 m/roll (1) and (3) gives:
= 771.43 /paper processed roll (9) 20 rolls
15 428.6 m /paper roll2
m2
≈ 8 min (10) 800 m /min
6430 m/ paper roll
20 minutes of manual handling time will be required before and after processing.
= 20+8+20 = 48 min
P /Trewinding machine
(eq. 1-2) gives:
=
=
2.4 min = 144 s C/Trewinding machine 48 min20 units
Main machine
The main machine is going to be the most loaded resource in the facility. It the process where the actual value for the customer will be generated. The main machine can be seen as one process in which several subprocesses are included. Whether beams or rods are going to be manufactured, a fully charged main machine requires 9 processed rolls. Adjustments regarding the product’s length and feeding rate can take place while the machine is still producing. The only setup time is when the profile dimension is changed. Therefore, two main machines will be obtained in order to minimize the number of setup times.
Given parameters:
= 95%
η
main machine= 30 m/min
v
main machineSetup time (S/T) = 120 min
Figure 17: Simplified sketch of the main machine, viewed from above.
Calculations
(8) gives:
(771.43 m2/ processed roll)*(9 processed rolls) = 6943 m2 (11)
Beams
(11) gives:
= 1118 beams 6943 m2
2.07 m /m beam 3 m2 * (12)
Time until paper needs to be refilled in the main machine working 5-shift:
= 3354 m beam (13) 6943 m2
2.07 m /meter beam2
(13) gives:
= 111.801 min ≈ 1h 52 min (14) 3354 m
30 m/min
≈ 2h P /Tpaper 5−shift
(12), (14) and (eq. 1-2) gives:
=
≈
0.1 min = 6 s (15) C/Tpaper 5−shift 111.801 min1118 beamsRods
(11) gives:
= 5418 rods (16) 6943 m2
1.44 m /m rod 0.892 *
Time until paper needs to be refilled in the main machine working 2-shift:
= 4822 m rod (17) 6943 m2
1.44 m /meter rod2
(17) gives:
= 160,7 min ≈ 2 h 41 min (18) 4822 m
30 m/min
≈ 3h P /Tpaper 2−shift
(16), (18) and (eq. 1-2) gives:
=
≈
0.03 min ≈ 2 s (19) C/Tpaper 2−shift 160.7 min5418 beams
Production takt time
The following calculations are based on that the customer demand for the requested annual volume is equally distributed throughout the 45 weeks of production.
Beams
Yearly demand: 14.6* 106 m beam
Dimension: Profile dimension 45x70mm with a length of 3.0 m Available working hours per day: 24h
Shift: 5-shift (06-14), (14-22), (22-06) including weekends
= 324 444 m beam/week (20) 45 weeks
14.6 10 m beam* 6
≈
46349 m/ day (21) 7 days3244444 m
≈ 15450 beams/day (22) 3m
46349 m beam/day
(eq. 1-1) and (22) gives:
= = 0.00156 days = 0.00156*24*60= 2.23 min (23) (T akt time)beams 15450 24
Rods
Yearly demand: 5 * 10.0 6 m rod
Dimension: Profile dimension 14x67 mm with a length of 0.89 m Available working hours per day: 16h
Shift: 2-shift (06-14),(14-22)
= 111 111 m rod/week 45 rod
5.0 10 m rod* 6 (24)
≈
22222 m rod/ day 5 day111111 m rod
(25)
≈ 24 969 rods/day (26) 222220.89
(eq. 1-1) and (26) gives:
= = 0.000641 days = 0.000641*24*60*60 ≈ 55 s (27) (T akt time)rods 24969 16
4.3.1 Scenario 1
This scenario presents the maximum volume that can be produced for 45 weeks by the two machines.
The capacity of the two machines is used to their fullest extent. No customer demand is involved.
Limitations:
● 45 weeks for production are available
● Two main machines working 2-shift respectively 5-shift
● The machines are used to their fullest extent with consideration to their shift-time Main machine producing beams, 5-shift
Avalible working time = 45*7*24 = 7560 h = 453 600 min
