Preface
A couple years ago ‐ after finishing Business Economics at the HBO in Enschede ‐ I did not have the feeling that I learned enough and that I was ready to work. So, I decided to extent my student career. As I had seen the city of Groningen (and experienced its nightlife) a couple times before, the city of interest was an easy pick. The choice for the (pre) master 'Operations & Supply Chain' at the Faculty of Economics and Business was also a quick one. This work right in front of you, which contains the description of a research conducted at Eaton Electric B.V. in Hengelo, is the final step of this master. Eaton Electric B.V. is a production company that produces components and systems in the low and middle voltage segments for electrical distribution. This research is about one of Eaton's products in the middle voltage segment, the so‐called Xiria. I spend my time at Eaton with the people of the Opex department. The lean specialist in the (Op)erational (Ex)cellence department identify possibilities for improvement within every aspect of the company. For me, my colleagues at the Opex department turned out to be very funny and social, but above all hard working and dedicated. I had a great time and would like to thank them for that. A special thank goes out to Tom Vleerbos ‐ my supervisor at Eaton ‐ who gave me the opportunity to graduate there, and who had the willingness to listen to everything I had to say. Unfortunately for Eaton, Tom has recently moved into the position of aldermen in the municipality of Tubbergen. I would like to take this opportunity to wish him all the best with that responsible job. It has taken me longer to finished my thesis than I had hoped and expected, but I am satisfied with the results. For that, I owe a big thanks to my supervisor at the RUG, Mark Mobach. He took the time and patience to guide me, and to show me the right direction. Mark's support, criticism, and suggestions during this work are greatly appreciated. A special thanks goes out to my family and my girlfriend Marsha. All of them have stayed positive throughout and supported me at times when I wasn't happy about it. Without their constant support and encouragement, this thesis would probably not have seen "the light of day”. Finally, I would like to express my appreciation to everybody else that helped me finish my courses and thesis. I learned a lot of all of you, but most importantly, I had a great time!
Abstract
Production facilities such as Eaton have a large number of tasks ‐ each with its own purpose and direction ‐ that are related some way. Tasks very in complexity and are often split in two or more tasks. To avoid disintegration of those tasks that are pulled apart, so‐called coordination mechanisms and design parameters are used to link the system and to control this link. In this research, the tasks needed to assemble a Xiria and the way these tasks are linked and controlled is discussed and evaluated based on the physical suits of the organization. The research question is:
Is the Xiria assembly line designed in the most efficient way, if not, where and how can adjustments be made to improve it?
In literature the physical suits of the organization is known as facility design. Facility design consists of several components of which the microelement of facility design (layout design and handling system design) are discussed in this research. The SLP methodology of Muther (1973), the Material Handling Equation of Apple (1977) and a checklist based on what is regarded efficient in literature are used to describe and evaluate the layout design and handling system design of the Xiria facility.
The results of the evaluation shows that Eaton has designed its Xiria facility efficient on several criteria, but that also improvements can be made to increase efficiency. To improve the efficiency based on the objectives and criteria used in this research, the layout (U‐shaped one is recommended) and handling systems design (sequenced supply is recommended) must be redesigned.
1. In troduction
Chapter 1. Introduction
This chapter aims to give the reader a better understanding about where this research has been accomplished. It will provide insight in the organizational structure of the Eaton Corporation, how Eaton Electric B.V. is contributing to the Eaton Corporation and what tools and philosophies are being used in the company. The chapter will end with an introduction of the product Xiria and its developments in the market over time.
1.1 The Corporation Eaton
Eaton as an corporation is a diversified industrial manufacturer with sales of approximately $13.0 billion. The Eaton Corporation has five business segments, Electrical, Hydraulics, Aerospace, Truck and Automotive. With 82.000 employees it produces and sells products in more than 150 countries. Eaton has the vision to become a premier diversified industrial manufacturer, to be the most admired organization in its markets. The mission of Eaton is to produce products with the highest quality against cost which can compete in markets where the prices are determined by free competition. The Eaton Corporation uses the Eaton Business System (EBS) to link Eaton's worldwide businesses and employees. The EBS is a set of common values, philosophies, management tools and measures. The EBS enables Eaton to systematically manage its businesses while capturing the benefits of diversity, scale and rapid transfer of best practices. EBS positively impacts the results by improving working capital and operating margins and reducing costs through the following elements: Corporate Goals, Planning, Growth, Execution, Assessment and Tools. One of the tools of the EBS most in line with the research is the ELS – Eaton Lean System.
1. In troduction standard condition is visible, and it seek to involve all the team members in all these activities, since they are the wellspring of continuous improvement (Shook, 2007). Operational Excellence (Opex), a special department, is established within Eaton. In this department, lean specialists identify possibilities for improvement, and these specialist have the responsibility to implement the ELS by teaching other departments the ELS and facilitate and advise them during implementation of the ELS tools and culture. This research has been conducted at the Opex department. Since the decision of using ELS has already been made, the author will not question whether lean is the right thing. However, it is important that whatever recommendations this thesis delivers it must go along with the ELS in order to get Eaton and even OPEX to consider implementing it.
1.2 Eaton Electric B.V.
Eaton Electric B.V. is part of the Eaton Electric Division in Europe. Eaton Electric B.V. is located in Hengelo and produces components and systems in the low‐ and middle voltage segments for electrical distribution, control and protection. Eaton Electric B.V. offers switchgear systems and components for energy distribution in main stations, sub distribution stations, transformer stations, cable distribution and residential applications. The components can deal with voltages between 1000 V (low voltage) and 36000 V (middle voltage). The products of Eaton Electric B.V. are suitable for almost the whole energy network – see figure 1 – from main feeder station to residential applications.
Figure 1 The Energy Network
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segment MVS is object segment of this research. Further on, when the term Eaton is used, the researcher means Eaton Electric B.V.
1.3 Xiria
One of Eaton’s products in the MVS segment is Xiria. The Xiria is a distribution station and is made for applications till 24kV. A Xiria is a ring main unit and is one of the newest product of a generation of ring main units within Eaton. Around the millennium the Xiria is developed as an answer to the liberalization at the energy market. Liberalization made that electricity became more and more a commercial product and that energy distributors were becoming more cost aware. These cost aware customers are served with the maintenance free system of Xiria. One of the differences of the Xiria to its competitors is that the product is very compact and is known for its outstanding reliability. The installation and the mechanism of the product are covered in a sealed cover, an important feature of the reliability. Xiria is designed with a fully enclosed metal housing combined with single phase insulation of all primary live parts. This reduces the risk of an internal fault to an absolute minimum, thus providing a high degree of safety and availability. Unlike its competitors a Xiria does not contain damaging gasses which protect the installation inside. Instead, the volume around the installation is made vacuum, which does not harm the environment. This makes the Xiria distinctive for the environmental aware customer. Xiria units can be used in compact transformer stations for energy distribution and in accessible stations in utilities and industry. They are also ideal for use in decentralized power generation systems such as wind farms.
Figure 2 A 3F Xiria installation
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A Xiria unit consists out of a basic frame which has two (2), three (3), four (4), or (5) Fields (2F, 3F, 4F, 5F). F is an abbreviation of the term ‘Field’. Figure 2 is a 3F, see the 3 different fields that can be distinguished on the picture. The number of fields (F) play an important role at the amount of tasks a Xiria can perform. Basically, two field versions are available:
a vacuum load‐break switch for ring cable connections; (short name is: K)
a vacuum circuit‐breaker for the protection of mains transformers and cable connections (short name is T).
Both, a K or a T field, can be supplied in 12kV and 24kV, and can be added to the frame in any combination and sequence possible. For example, customers can order a 3F KKK, KTK, TKK, TTT, etc., whatever combination possible. Not only the customer can choose between the amount of fields, the version of the field (K or T), and voltage they want (12kV and 24kV), there are also different options. The following options can be added on a Xiria: Remote signaling Electric remote control Motor steering Arch support Bottom plates On a baseboard
Therefore, the choice between a 2F, 3F, 4F or 5F, a K or T field, between 12kV or 24kV, and the different customer options make that a lot of variants are possible. The potential number of various products that can be produced lies in the millions, though the basic components are the same across all customer orders.
1.4 Xiria production
1. In troduction EEGS The Xiria frame is produced in‐house by Eaton Electric General Supplies (EEGS). EEGS is an internal supplier of Eaton and employs about 130 people. EEGS produces and supplies components needed to assembly the low voltage and medium voltage systems on the assembly floor. EEGS produces a very wide range of components of different materials (copper, metal, aluminium). Many components are standard components which are needed for every assembly of a typical product. EEGS itself is divided in several departments: sheetmetal, copperbar, and punching. The names of the departments give an indication of what kind of operations they perform. EEGS can be seen as a important link in the supply chain of most of the assembly lines in Hengelo. Suppliers of EEGS deliver raw material to EEGS and EEGS delivers a semi‐manufactured product to the assembly lines.
EEGS is Xiria’s main supplier. More than 90 components (of in total ± 300) for the different Xiria versions are produced by EEGS, under which the most important one, the Xiria frame. The frame is the fundament of a Xiria. Every other component is attached to it. The frame is constructed out of sheet metal parts and is welded by EEGS. The wide of the frames of the 2F, 3F, 4F, and 5F differ but the frames have an equal height and dept. The Xiria frame is built up out of raw sheet metal. The first job is to punch the sheet metal. Then they need to be bended in the right form. Sometimes some extra work on a bench has to take place, mostly attaching some little parts (like screws) on the articles. The welding robot takes over for the next step. The robotic welding frame exists out of welding the frame and stud welding. The studs are necessary parts for later in the assembly process. The studs make sure that all the needed materials can be attached to the frame. After the necessary quality checks, the welded frame goes to the powder coating. Then, some side plates are attached to the frame, and after drying the frame is ready to be transported to the Xiria assembly line.
Cast Resin
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Concluding, a Xiria consist of a sheet metal frame, on which all other material is attached at the assembly line. The frame is produced by EEGS. Besides the frame, EEGS produces several other sheet metal plates for the on lay of the Xiria. Cast Resin produces the epoxy resin for the current flow or conductance. Both departments produce material that determine for a large part the design and functionality of the Xiria. Figure 3 shows a selection of the materials produced by EEGS and Cast Resin.
Figure 3 Materials produced by EEGS and Cast Resin
1.5 Xiria developments
From 2003 till 2008, Eaton was producing two product variants at the Xiria assembly line. The 3F and 4F version. However, due to customer demand the 2F and 5F version have been introduced. In the next figure (graph 1) one can see what marketing thinks to sell the upcoming years.Graph 1 (Expected) Customer demand over the years
This graph shows that the expectation for Xiria are high. Eaton expects a steady grow for the ‘old’ 3F and 4F versions, and thinks that the 2F will become a good third. They do not think that the demand for a 5F will be high, but a considerable sales amount of these units is expected. Next to the introduction of the new versions, an increasing demand in options and special customized solutions can be notified. To illustrate this, the demand for Xiria’s over the last couple of years has been analyzed.
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2. Researc h desi gn
Chapter 2. Research design
The purpose of this chapter is to provided the reader the outline and content of this thesis. The research question and sub‐questions are discussed in the first paragraph. Then, the limiting conditions, scope, level of analysis, choice of the subsystem, and the research model are discussed to provided the operational description of this research.
2.1 Research question
Production facilities such as Eaton have a large number of tasks. These tasks are always related in a certain way. The complexity of the tasks and their interdependencies in the organization can vary. Literature distinguish simple, complicated and complex organizations. The organization of tasks and their dependencies provides a certain output, such as a product or service. In the simplest organizations, for example a hot dog stand, only a few activities are related to each other. As the number of activities increases, and the differences and dependencies between them as well, an organization will become complicated. Complex organizations, like many productions facilities, distinguished themselves by the large quantity of various functions that occur in it, not necessarily by their complexity. Only when the tasks and dependencies change in nature and content over time and prediction of the outcome is difficult, an organization is complex. Changes in activities and dependencies exists in almost every organization, including in a hot dog stand, but the extent and rate of change and the nature of the change can vary greatly. This is why one organization is complex and the other not (Mobach, 2009).
2. Researc h desi gn
The link between tasks, coordination and design parameters is large. By employing vertical decentralization for example, more room for direct supervision is created, but then liaison is necessary for achieving mutual adjustment. So, by implementing the design parameters in a way behavior in the organization is composed and structured (Mobach, 2009). This structure, which embodies the final ordering of the manufacturing process within the properties of a facility, is called facility design.
The goal of the research is to examine ‐ by describing, analyzing and evaluating ‐ the facility design of the Xiria assembly line, and whether, and if so, where in the facility design improvements can be made. The research question is therefore:
Is the Xiria assembly line designed in the most efficient way, if not, where an how can adjustments be made to improve it?
To answer this research question several sub‐questions must be answered. First the design of the assembly line must be described and analyzed. The first sub‐question is therefore:
1. What are the properties of a facility?
In this research, the term efficiency captures the amount of desirable and undesirable features within the assembly line design. The more desirable features, the better. What desirable is and what not must be explored within the literature of facility design. In other words, the design of the Xiria facility must be evaluated by features (objectives) regarded efficient in literature. So, the second sub‐ question is: 2. What objectives can be used to evaluate the efficiency of the design of a facility, and which will be used to evaluate the design of the Xiria facility?
When these first two sub‐questions have been answered the design of the Xiria facility can be described and evaluated, and then the third and last sub question can be answered:
3. How efficient is the design of the Xiria facility based on the objectives chosen, and how / where can it be improved?
2.2 Limiting condition
The limiting conditions describe requirements and restrictions of the research, where the results and methods are subjected to. In this research the design of the Xiria assembly facility is revisited, not redesigned. The objective is to give Eaton applicable recommendations to improve performance of the assembly line by (small) adjustments in design of the facility. The limiting conditions are:
2. Researc h desi gn The research is limited to the Xiria assembly line alone. Note that this final limitation has its limitations on its own, since the design of the overall facility (the assembly plant, EEGS and Cast Resin) is influencing the design of an individual assembly facility. This ‐ for this research ‐ challenging limitation might influence the applicability of the results and recommendations.
2.3 Scope
The scope of this research is limited to the Xiria assembly facility. The other assembly facilities of the Eaton plant, as well as the departments EEGS and Cast Resin are out of scope. However, EEGS and Cast Resin are definitely part of the total production process of the Xiria applications. Therefore, it will be impossible to ignore them completely because tasks and dependencies between the Xiria assembly line and EEGS / Cast Resin do have some overlap. Secondly, this research will diagnose the design of the Xiria assembly facility, and concluded with recommendations for improvement. Due to time constraint the implementation of the recommendations are out of scope.2.4 Level of analysis
The word design has many different meanings. To some it means the aesthetic design of a product, such as the external shape of a car or the color, texture, and shape of the casing of a can opener. In another sense, design can mean establishing the basic parameters of a system or process. It might be obvious that this research is interested in the this latter part of design. There is an extensive amount of literature about designing a system (or facility, plant, operation etc.) to produce a product or service. The treatment of facility design as a subject has ranged from checklist, cookbook‐type approaches to highly sophisticated mathematical modeling (Tompkins et al., 2004). In this research however, the intention is to employ a practical approach to facility design on a micro design level. The scope is limited to the design of the Xiria assembly facility alone, which automatically asks for a more detailed perspective of facility design (see chapter 3) and therefore a lower level of analysis. However, to provide a better understanding of the Xiria product and its facility a higher level of analysis is needed as well. Most of this higher level of analysis has been provided in the first chapter.2.5 Choice of the subsystem
2. Researc h desi gn
limited to only a small amount of tasks of the overall (Xiria) system. While a small subsystem is examined, all the dependencies and relations within this system are for interest of this research. In the theoretical background chapter the concept of facility design will be explained more thoroughly. It cannot be unnoticed that facility design is part of a bigger concept named facility planning. However, this research is limited to the microelements of facility planning (of which facility design is one). It is because of the scope of this research, and the choice of the subsystem that only two concepts of facility design ‐ handling systems design and layout design ‐ are considered.
2.6 Research model
The following figure is the conceptual model of this research.Figure 4 Conceptual model
2. Researc h desi gn
Next, in the theoretical background chapter, the properties of a facility and the objectives used to evaluate the design of the Xiria assembly line will be discussed.
3. Th eoretical background
Chapter 3. Theoretical background
Facility design will be discussed and the first two sub‐questions of this research will be answered in this paragraph. The first paragraph explains the facility design concepts that are of interest of this research. Based on the concepts of the first paragraph the second, third and fourth paragraph of this chapter discuss the first two sub‐questions.
3.1 Facilities design
Facilities are created to help organizations to achieve their goals. The creation of a facility is called facility planning. Plant layout was the expression used by the pioneers in facilities planning. The terms physical arrangement, efficiency, workforce, materials and machinery are an integral part of each definition of plant layout. The most complete definition of that time is (Moore, 1962): "Plan of, or the act of planning, an optimum arrangement of industrial facilities, including personnel, operating equipment, storage space, materials handling equipment, and all other supporting services, along with the design of the best structure to contain these facilities. Good plant layout is fundamental to the operation of an efficient industrial organization."
Moore (1962) emphasizes that the term optimum is related to whatever criteria may be chosen to evaluate a plant layout. Later on the term optimum was substituted by the word efficiency. The change from plant layout to facility layout occurred in the early 1970's. However, the confusion between the terms design and layout lasted. In the 1990's several authors developed new definitions, but only detailing certain elements, or adding others. Considering these various definitions, Marcous, Roipel, Langevin (2003) updated the definition of facilities layout: "The physical arrangement in a certain space of all activities (e.g., production, handling, warehousing, and services to production and staff) related to materials, equipment and workforce to allow efficient production according to market specifications."
In parallel with the definition of facilities layout, the concepts of facilities planning and facilities design must be clarified. Tompkins and White (1984) formalized a hierarchy linking those concepts (see figure 5).
3. Th eoretical background Figure 5 Facility design concepts
The location of the facility refers to its placement with respect to customer, suppliers, and other facilities with which it interfaces. The design components of a facility consists of the facility systems, the layout, and the handling system. Facility systems design consist of the structural systems, the atmospheric systems, the enclosure systems, the lighting/electrical /communication systems, the life safety systems, and the sanitation systems. The layout consists of all equipment, machinery, and furnishing within the building envelope needed to perform all the necessary tasks. The handling system is mechanism needed to satisfy the required interactions between tasks and dependencies within the facility.
Facility location addresses the macro issues, whereas facility design looks at the microelements of designing a facility. This research is interested in the latter microelements of the Xiria facility; layout design and handling systems design. The layout design and the material handling design are inseparable (Tompkins et al, 2003). Handling decisions can have a significant impact on the efficiency of a layout and every consideration affects the requirements for space, equipment and personnel. Therefore, to evaluate the facility design of the Xiria facility, the layout and the handling system design should be discussed, described and (re)designed simultaneously. In the next paragraphs, two methodologies for describing and analyzing the layout design and handling systems design are discussed. Facility systems design is out of scope, since this is more related to the overall Eaton facility instead of the Xiria facility alone.
3.2 Layout design
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analyze the current Xiria assembly line layout. Because of this difference, some modification have been made to the methodology to make it applicable for this research.
3.2.1 SLP
According to Muther (1973) the SLP consist of four phases. The SLP procedure as detailed in figure 6 can be segmented into four phases
containing 11 steps. Phases 1 is the inputting of data as follows: Step 1: P (product), Q (quantity), R (route), S (support), T (time) Step 2: Flows of material Step 3: Activity relationships Step 5: Space requirements Step 6: Space available Step 8: Modifying constraints Step 9: Practical limitation The second phase is the procedure process, which is represented by: Step 4: Relationship diagram Step 7: Space relationship diagram The third phase is output result, which is: Step 10: developing layout alternatives The last phase is the evaluation process: Step 11: Evaluation Phase 1 In the first step of the first phase the PQRST are determined. The PQRST are the inputs of the facility. Possible questions for every character are (Muther, 1973): P: Which products are produced? What are the characteristics of the materials used? Q: In what quantity are they produced? R: Where are the products coming from, and where are they stored? S: What is used to control the material movement and production. T: How is the production planned (in time). In the second and third step the material flow and activity relationships are analyzed. Both are kind of the same, but the activity relationship is based on the material flow analysis and supporting
3. Th eoretical background activities. Other data is collected as well in the first phase, as shown in steps five, six, eight and nine. The data collected in the phase is used as inputs for the other phases. Phase 2
The second phase starts with the creation of the relationship diagram. The relationship diagram reveals a good positioning decision among the functional areas, it provides an overview of the closeness relationship, and is used to analyze the relationships between tasks and the positioning of the related ones. In SLP, the relationship diagram is also used as input for the space relationship diagramming decisions (Muther, 1973).
Phase 3:
3. Th eoretical background Step 9: Layout improvements The first phase of the modified SLP is used to describe the P Q R S T inputs, the flow of assembly, and the relationships between the tasks. Due to the scope of this research the space requirements, space availability, modifying constraints and practical limitations are not included, since the location of the Xiria facility within the plant is permanent, and no additional floor space is available (see limiting conditions). Step 7 in the procedure process (space relationship diagram), has been changed in individual task design. This has been done since the definition of facility design learned us that “space of all activities is related to materials, equipment and workforce”, so by describing the equipment, materials and workforce space of the individual tasks the space utilization can be analyzed and the layout design can be evaluated as well. The last phase is the presentation of the improvements that can be made.
3.3 Handling system design
The design of the handling system is an important component of the overall facility design. The layout design and the material handling system design are inseparable (Tompkins et al, 2003). The relationship between the two involves the data required for designing each activity, their common objectives, the effect on space, and the flow pattern. This is why the layout design and handling system design should always be discussed jointly (Sule, 1988). To help guide the description and analysis of the current handling system design, the (material) handling system equation by Apple (1977) can be used.
3.3.1 Material handling system equation
To help guide the development of alternative material handling systems designs, Apple (1977) suggested the use of the material handling equation. The material handling system equation gives a framework for identifying solutions to material
handling problems (Heragu, 2006). As shown in figure 7, it involves seeking thorough answers to six major questions. The what defines the type of materials moved, the where and when identify the place and time requirements, the how and who point to the material handling methods. A detailed listing of the what, where, when, how,
3. Th eoretical background The material handling system equation questions is very helpful in making a handling system design analysis. To answer the What question, parts and material lists and production schedules are good sources of information. For answering the Where question, process charts, flow diagrams, and scale models of the plant are some of the sources from which these data can be gathered. Operations charts and time study data can be used to answer the When en How questions (Sule, 1988). Note that some of the methods mentioned by Sule (1988) have overlap with methods used in the SLP (flow diagrams, scale models etc.). This again stresses the fact that the layout design and the handling design are inseparable and should be discussed jointly.
Hence, the Systematic Layout Procedure, developed by Muther (1973), will be used to describe and analyze the layout design of the Xiria assembly line, and the material handling system equation for the handling system design. Once these two methodologies have been discussed, the information must be examined for possible improvements. The results of the SLP and the material handling system equation will be used as guidance as to where improvements can be made. However, assessing a facility requires defining objectives on which it can be evaluated. The next and last paragraph of this chapter will define these objectives.
3.4 Evaluation criteria
Several authors present a more or less exhaustive list of objectives to consider. Muther (1973) proposed 20 key points to consider in making an evaluation of a facility. More recently, Tompkins et al. (2003) enumerate 35 criteria for evaluating a facility. Table 1 presents a list of objectives quoted by various authors and made by Marcoux, Riopel and Langevin (2005). These objectives are classified as strategic, tactical, and operational. Whereas the scope of this research is limited to the microelements of facility design, the strategic objectives (more facility location related) are not considered. The Xiria facility will be evaluated on some of the tactical and operational objectives of table 1. The scope of this research and its time constraint is the main reasons for choosing only a couple of these objectives. The decision of which, is based on the Eaton lean strategy, since Eaton is in fully process of implementing the lean philosophy. Therefore, lets discuss this lean philosophy shortly.
3. Th eoretical background Strategic objectives Be able to meet forecasted capacity needs (adaptability and versatility) Muther (1973), Wrennal (2001), Tompkins et al. (2003) Plan for future expansion Reed (1961), Muther (1973), Cedarleaf (1994), Sheth (1995), Tompkins et al. (2003) Be consistent with company image, appearance, promotional value, public or community relations Reed (1961), Muther (1973), Wrennal (2001), Tompkins et al. (2003) Optimize capital investment Moore (1962), Apple (1963), Muther (1973), Sheth (1995), Tompkins et al. (2003) Minimize impact on production during the installation period Tompkins et al. (2003) Minimize negative effect on environment Tompkins et al. (2003) Integrate with external elements Muther (1973), Tompkins et al. (2003) Tactical objectives Fit with organization structure Muther (1973), Tompkins et al. (2003) Facilitate supervision, control and communication Muther (1973), Apple (1977), Heragu (1997), Tompkins et al. (2003) Optimize space requirements Moore (1962), Apple (1963), Muther (1973), Sheth (1995), Heragu (1997),Tompkins et al. (2003) Provide overall simplification, standardization Moore (1962), Apple (1963) Maintain flexibility of arrangement and of operations Reed (1961), Apple (1963), Muther (1973), Sheth (1995), Tompkins et al. (2003) Maximize storage and supporting services Apple (1977), Muther (1973), Tompkins et al. (2003) Optimize use of natural conditions, building or surroundings Muther (1973) Facilitate maintenance and housekeeping Muther (1973), Apple (1977), Tompkins et al. (2003) Consider needs of workers with disabilities Cedarleaf (1994) Operational objectives Provide high WIP turnover Moore (1962), Apple (1977), Wrennal (2001) Optimize flow (materials, information and personnel) Muther (1973), Heragu (1997), Apple (1977), Cedarleaf (1994) Optimize handling (e.g., minimize cost of materials handling) Moore (1962), Apple (1963), Muther (1973), Heragu (1997), Cedarleaf (1994), Tompkins et al. (2003) Promote safety and security of materials, equipment and employees Moore (1962), Apple (1963), Muther (1973), Sheth (1995), Heragu (1997), Tompkins et al. (2003) Provide convenience for workers & promote job satisfaction Moore (1962), Apple (1963), Muther (1973), Heragu (1997), Tompkins et al. (2003) Optimize use of equipment Apple (1977), Muther (1973), Tompkins et al. (2003) Stimulate optimal workforce utilization Moore (1962), Apple (1963), Tompkins et al. (2003)
Table 1 Facility design evaluation criteria
3.4.1 Lean philosophy
3. Th eoretical background increases the cost of production and time of delivery to customers. Waste is something the customer is not willing to pay for, which is the opposite of value, which is simply what a customer is willing to pay for. The most common sources of waste in a manufacturing facility are equipment, inventories, space, time, labor, handling, transportation and paperwork (Tompkins et al., 2003). The 7 wastes described by Ohno (1988) are: 1. Overproduction and early production producing over customer orders, producing unordered materials / goods. 2. Waiting ‐ hanging around, idle time (time when no value is added to the product) . 3. Transportation ‐ handling more than once, delays in moving materials, unnecessary moving or handling . 4. Inventory ‐ unnecessary raw materials in stores, work in process (WIP), & finished stocks . 5. Motion ‐ movement of equipment or people that add no value to the product .
6. Over‐processing ‐ unnecessary processing or procedures (work carried out on the product which adds no value) .
7. Defective units producing or reworking scrap.
However, the lean system is much more than a scavenger hunt for waste. While the core of lean is the elimination of waste, the lean organizations are built on visibility, simplicity, flexibility, standardization and organization (Tompkins et al., 2003). Lean tries to seek continuous flow so that the customer can pull. It wants to create simplicity so that any impediment to flow is readily apparent. It wants to employ visual management so that the out‐of‐standard condition is visible, and it seek to involve all the team members in all these activities, since they are the wellspring of continuous improvement (Shook, 2007). Many of the lean concepts and techniques impact the facility layout, and the handling system. For example, visibility can be obtained by electronic boards for quick feedback, pull system with kanban, colored standard containers, decentralized storage systems. Simplicity can be achieved with simple setup changes, simple material handling, simple machines, small lot sizes etc. Flexibility can be achieved with short setup times, flexible material handling, multifunctional employees etc. Hence, since Eaton is in fully process of implementing the lean philosophy in every aspect of its organization, the objectives chosen to evaluate the facility design of Xiria ‐ based on facility design literature of table 1 ‐ are those objectives that are closely related to that lean philosophy. The following objectives are chosen:
3. Th eoretical background Facilitate supervision, control and communication (Optimize) space (requirements) 3.4.2 Flow In an ideal lean situation the production processes are based on the actual customer demand, and when customer demand occurs, the order flows through the processing steps from raw material to the customer without any delays or wastage. This producing and moving one item at a time (or a small and consistent batch of items) through a series of processing steps as continuously as possible, with each step making just what is requested by the next step, is called one‐piece flow. In a pure one‐piece‐flow process there are no hidden wastes and there is no variation that cause buffers (Liker and Meier 2006). With continuous flow production it is possible to precisely know when an order starts, and when an order is finished due to the predictability of the process. The material flow will be more stable through the whole supply chain. The stable demand of materials will also cause a decrease in inventory levels, since it is know when and where materials are needed. Hence, flow reduces waste and this is why Eaton tries to obtain it. To create flow in lean, the production schedule must be leveled appropriately and products are pulled when needed and in the quantities needed (Liker and Meier, 2002). However, the physical process itself must also be designed to make flow as efficiently as possible. Efficient flow patterns within a facility includes the progressive movement of materials, information, or people between departments, between workstations and through workstation (Tompkins et al., 2003). Therefore, the work elements of a facility must be laid out so that no inventory can be accumulated between tasks, excessive walking is eliminated, no obstacles are in walking paths, and tasks are as close to one another as possible, etc.
3.4.3 Handling
3. Th eoretical background 3.4.5 Supervision, control and communication
Continuous improvement is a driving principle of lean. A lean company focuses upon continuous improvement of processes in manufacturing, engineering, supporting business processes, and management. The core principle of continuous improvement is the (self) reflection of processes. The purpose of continuous improvement is the identification, reduction, and elimination of suboptimal processes. To be successful in continuously improving, the participation of workers is essential (Womack and Jones, 2003). Supervision, control and especially communication are important for identifying suboptimal processes and to create a culture of innovation and creativity. The design of a facility influences the ease of supervision and control and the amount of communication among workers (Tompkins et al., 2003). Therefore, the ease of supervision and control and the amount of communication among workers influence the swiftness of the continuous improvement process.
3.4.6 Space
3.
Th
eoretical
background
Hence, flow, handling, flexibility, supervision, control and communication, and space are the 5 objectives where the Xiria facility will be assessed on. Now we know this, the conceptual model of chapter 3 can be adapted to its final state:
Figure 8 Final conceptual model
3.4.7 Checklist for evaluating flow, handling, flexibility, communication and space
Literature has provided several extensive checklists for evaluating layout design and material handling design. Based on the rule of thumbs of material handling, Tompkins et al. (2003) have constructed a material handling checklist (see appendix 3). Sule (1988) also provides a material handling checklist (see appendix 4). Liker and Meier (2006) constructed a lean material management checklist and a cell layout design checklist (appendix 5). In their books, Tompkins et al. (2003) and Sule (1988) provided several other criteria for facility design. These criteria have been listed by the researcher (including page references). An overview of these criteria can be seen in appendix (6). Based on all these checklists and criteria in appendix (3, 4, 5, and 6), and on the discussion in the previous paragraphs, the researcher has made a combined evaluation checklist for evaluating efficiency of the layout and material handling design based on the objectives, flow, handling, flexibility, supervision, control and communication, and space (see appendix 7). This checklist is used to evaluate the facility design of Xiria in the next chapter.
4. Th e Xiria faci lity
Chapter 4. The Xiria facility
This chapter' purpose is the description of the layout and handling systems design of the Xiria facility, and the evaluation of that design. The description is led by the modified SLP methodology and the material handling system equation. At the end of this chapter, the reader will know how the Xiria facility is currently designed, how efficient this design is, and where the facility design can be improved.4.1 Layout design
Muther's SLP methodology is used to describe the layout design of the Xiria assembly line. The first step of the SLP methodology is the identification of the products and materials. The Xiria installations (P) have already been introduced in the first chapter, therefore the P,Q,R,S,T paragraph will mainly focus on the Q,R,S, and T. 4.1.1 P Q R S T4. Th e Xiria faci lity
complete explanation of all these concepts the author recommends the books; Learning to See by Rother and Shook (1999), The Toyota way Fieldbook by Liker and Meier (2006), Creating Mixed Model Value Stream by Duggan (2002), or other lean theory books.
Mixed model production stands for a factory producing close to the mix of different products that are sold that day or as Duggan (2002) states: “mixed‐model production means producing a mix of products or product variations through the same value stream at the pull of the customer. This means to build and deliver the right quantity of a specific product (out of a high number of products available) when the customer wants it.” As Liker and Meier (2006) state in their book; "the ideal situation in mixed model production, is that the products continuously flow through the line, one piece at a time without stoppage according to the rate of customer demand. Takt time is the customer demand rate. It guides the assembly how quickly it should produce". In mixed model production takt time is calculated at the pacemaker by dividing the effective working time by the total demand for all the various models running through the pacemaker (Duggan, 2002). The pacemaker is the scheduling point. The pacemaker is frequently the most downstream process in the door‐to door value stream, and is therefore often controlled by the outside customers orders (Rother and Shook, 2003).
4. Th e Xiria faci lity without too much idle time. The availability of production equipment and material alongside the line limits the walking distance and handling time of the operators which increases their value adding time. Kanban signals are used to regulate material replenishment based on the pull of the customer. The regulations of part replenishment based on kanban is good, since kanban bounds the amount of WIP in the system. This controlled amount of WIP or 'WIP cap' reduces congestions on the assembly floor and in aisles. It also makes the process easier to control and more efficient since less working capital is needed to finance unused or excessive inventory. 4.1.2 Flow of assembly
The second step in Muther's methodology is the description of the flow of assembly. The flow of assembly is being discussed by describing the different areas of the Xiria facility with different tasks that can be distinguished. The areas are: pre‐montage, fields in frame, components, high voltage test, and final montage. To help guide the description of the flow of assembly, the tasks and their relationships are being visualized in the a schematic model that is being extended after every description of the areas.
pre‐montage
The pre‐montage area has two workstation, the baseboard workstation and the assembly frame workstation. The baseboard workstation is only needed when the option on a baseboard is being assembled. The assembly frame workstation is one of the two starting points of the assembly line. At this workstation some sheet metal strips, a sheet metal back plate and a safety feature are attached to the frame. Figure 9 below show a 3F Xiria frame (left) and how the back plate is mounted onto the frame (right).
Figure 9 Tasks at pre-montage area: (left) a empty xiria frame, (right) mounted back plate on frame
After the pre‐montage is finished, the modified frame is brought to the next area (Fields in frame) where it used. The task where the frame is used in this area is the so‐called 'marriage' process. These tasks and their relationships are being visualized in the 'tasks at assembly line drawings'.
4. Th e Xiria faci lity Fields in frame The fields in frame area of the assembly line has several workstations and operations which succeed one another and because of that a roller track has been installed to support the flow. Several workstations are placed on both side of the roller track. In this area the operators assemble the fields which are later attached to the frame. The first task at the field assembly workstation is the assembly of a bracket. This bracket, a subassembly, is added into the field (see figure 10). Then several vacuum breakers are attached to the epoxy resins. After that some cuffs are attached to protect the fields against any discharge. Next at the divider houses workstation, several brackets, wheels, and springs are made to finish the fields. Then, at the connecting fields workstation, the side plates are mounted and the individual fields are compressed and linked.
Figure 10 Tasks at fiels in frame area: (left) vacuum breaker with epoxy resin, (middle) red brackets within a
field, (right) fields with side plates
Later on at the so‐called marriage workstation, the fields are attached to the already pre‐assembled frame. See tasks at assembly line, drawing 2 and figure 11:
Tasks at assembly line, drawing 2
Figure 11 Tasks at fields in frame area: (left) operator at marriage process, (right) connected fields, (under)
frame with fields after marriage process
Components
The next step in the process is the assembly of various electrical components. The first workstation adds a bearing slot to the fields. Then a front and several wires, covers, gauges, detectors and other material is added at the wiring workstations. When the options remote signaling, electric remote control, and motor steering are ordered they are assembled in this process as well. For a illustration of the components see figure 12. For a complete overview of all the tasks up to now see tasks at assembly line, drawing 3:
Figure 12 Tasks at components area: (left) the front of a field with a detector and several wires, (right up)
4. Th e Xiria faci lity Tasks at assembly line, drawing 3
High voltage test
At this area, the semi‐finished Xiria’s are tested in the high voltage cell. Since the assembly of the fields is now completed, the Xiria fields can now be tested on high voltage. Before the high voltage test a couple pre‐tests are needed. The fields are electrically inspected, and when problems are discovered they will be solved before the Xiria´s are transported to the next area. Figure 13 shows the high voltage test cell.
Figure 13 Tasks at high voltage test: (left) high voltage cell, (right) pre tests area
Tasks at assembly line, drawing 4
Final montage
4. Th e Xiria faci lity
Figure 14 tasks at final montage area: (left) white sheet metal plate attached to frame, (middle) glueing the
frame for the back plate, (right) back plate attached to frame
After this the Xiria is ‐ again ‐ electrically tested to make sure that all the different functions and options (if included) work. At the next workstation (the first of three final assembly workstations) an operator adds some strips to the bottom and side of the frame. Then, a certain substance is sprayed into the frame to test it for leaks. This substance makes it possible to observe a leak on the outside of the frame. Next, several styles, thresholds, doors, different cover plates and accessories (such as stickers, etc.) are added. When the option, on a baseboard, needs to be attached to the frame, it is mounted in this area as well (see figure 15 and 16). However as said before, the baseboard is being assembled at the area pre‐montage, and needs to be transported from there to this area.
Figure 15 tasks at final montage area: (left) thresholds being attached, (middle) a field door, (right) a
complete 4F Xiria with doors, cover plates and other accessories
Figure 16 tasks at final montage area: (left) a frame at the leak test, (middle) adding covers and doors to the
xiria, (right) a xiria on a baseboard
Finally, the Xiria undergoes a number of inspections, some descriptions of the product are added, and the Xiria is made ready for shipment.
This concludes the complete drawing of the tasks of the assembly line. See drawing 5 or appendix 8.
Tasks at assembly line, drawing 5 (final)
4. Th e Xiria faci lity 4.1.3 Tasks and relationships layout The model 'tasks at the assembly line drawing 5' visualizes the flow of assembly and the relationships of the tasks. As indicated before, every tasks in the drawing correspondents with a workstation at the assembly line. Therefore, the tasks and the layout (see appendix 9) of the Xiria assembly line have been combined into one illustration which is called 'task & relationship layout' (appendix 10). In the task & relationship layout the flow of the material though the assembly line has been drawn to better illustrate the physical relationships between the activities. When analyzing this layout and the relationships between the tasks a couple things stand out. These things have been highlighted with the letters A,B,C,D,E (see appendix 10). In short, a description of the marked letters:
A. As explained, the assembly starts at two different points. The first point is the assembly frame workstation in the pre‐assembly area, the other one is the field assembly in the field in frame area.
B. The frame and fields come together at the 'marriage' workstation (see tasks at assembly line drawing 1). The pre‐assembled frames are stored nearby the marriage workstation at the yellow section (see appendix 9). Sometimes the work in process accumulates at this yellow section. The workers at the pre‐montage area have some tensions to work up front. Working up front increase WIP, this limits the flow but also clutters the aisle and that slows down the material handlers. However, the yellow locations are prespecified WIP locations. So, WIP can accumulated there, as long as it is within the borders of the location.
C. At this point the components are added to the Xiria. When options ‐ remote signaling, electric remote control, motor steering ‐ are ordered they are assembled at the options workstations. Otherwise the Xiria is pushed forward to the first wiring workstation.
D. When options ‐ remote signaling, electric remote control, motor steering ‐ are ordered the functionality of these options is tested at the options testing workstation. When these options are not included the Xiria is directly pushed forward to the first final assembly workstation.
4. Th e Xiria faci lity
piece increases transportation and walking distances. This is not efficient and should be improved.
Hence, several areas with tasks can be distinguished at the Xiria facility. In all these areas, workstation have been designed to perform the tasks. The tasks of the workstations and their relationships are being visualized in the task & relationship layout. The facility has been designed to match the sequence of tasks and workstations, so workstations that are related are located next to each other. By physically locating workstation that are related next to each other, the walking distance is short and transportation and motion of materials, information and people is being limited. No or little transportation and motion waste increases the possibility of flowing without congestion and/or idleness, which increase the efficiency of the assembly line. However, some 'option' workstations must be regarded as exceptions. Especially the option workstation 'on a baseboard' stands out. Work piece is transferred from the front to the back of the assembly line, which is not efficient.
Then, the next paragraph will analyze even a lower level of facility design than this paragraph. Paragraph 4.1.4 will discuss the individual task design and the utilization of space. The individual design of the workstations determines mostly the utilization of space within a facility, which is an important objective of this research. Furthermore, by analyzing the individual design of the workstations the efficiency of these workstations with respect to for example operators handling, future expandability, ease of supervision and communication etc. can be discussed.
4.1.4 Individual task design
In the preceding paragraphs, the materials, the coordination, the control of the flow, and the relationships between the assembly tasks are discussed. This paragraph describe and evaluate the individual design of the workstations. Discussing the individual design of the workstations makes evaluating flow, handling, flexibility, supervision, control and communication possible and helps analyzing the utilization of space. So by also listing the space requirements for equipment, materials and workforce the space utilization can be described and analyzed. To guide the description in this paragraph, the five different areas ‐ pre‐montage, fields in frame, components, high voltage test, and final montage ‐ are again discussed. Remarks made about the design of the individual workstations are based on the objectives and criteria of the evaluation checklist of appendix 7.
Note for the reader: the author recommends appendix 10 and 11 as guidance when reading this paragraph.
4. Th e Xiria faci lity Pre‐montage (appendix 11.1) The assembly frame workstation is a small area where, as explained in the previous paragraph, some sheet metal strips, a sheet metal back plate and a safety feature are attached to the Xiria frame. Because the back plate has to be attached at the bottom of the frame, this workstation has a heft board for ergonomic reasons. The operator can pick up a Xiria frame from the inventory – Floor (FL) is the storage area for Xiria frames – put it on the heft board and directly do the necessary work, because no setup time is needed.
Since work needs to be done on both sides of the Xiria, material is stored on both sides of the workstation to limit the walking distance. The needed material is placed in prespecified locations and marked with barcodes for the kanban signals. Tools and other equipment are located close to the point of use and marked and labeled to visually identify locations of the necessary items, and when items are in use. No material is stored on the floor and the workplace is clear of unnecessary items. See appendix 11.1, pictures 3, 4 and 5.
The workstation where the baseboard is being assembled is located behind the storage space for the Xiria frames. This area is somewhat small and less net than the assembly frame workstation (see appendix 11.1, pictures 1 and 2). Some material is stored on the floor under the store racks and behind the store racks in the aisle. Also a office chair is available for operators to sit in. Whether or not an office chair is unnecessary and an obstacle for flow is debatable as well.
The operators at the assembly frame workstations and baseboard workstation are not able to communicate with each other, because the material is blocking their sights and sounds. The operators are also not able to communicated with the operators at the other areas because this area is not located directly in line with the others. This limits the supervision and control of this area and the swiftness of continuous improvement. Furthermore, the Xiria frame is needed at the marriage process in the fields in frame area and the baseboard on the other side of the assembly line at the final montage area. These workstations are not located closely, which increase the walking distance and transportation time.
