THE BEST WAY TO WORK: Increasing the efficiency through layout changes and standardization

THE BEST WAY TO WORK

Increasing the efficiency through layout changes and standardization

Lina Backéus

Industrial Design Engineering, master's level 2021

Luleå University of Technology

Department of Social Sciences, Technology and Arts

ABSTRACT

This is a master thesis done in the program of industrial design engineering at Luleå University of Technology, conducted during the spring of 2021. The project is a collaboration with Epiroc Rock Drills AB which is a leading global company in the mining industries, and the workshop in which this thesis is made manufactures and assembles rock drills sold worldwide. The aim of this thesis is to increase the utilization of three lathes in the workshop that are often left unused when their operators have to leave the machines to perform other tasks. This is due to short operation times that require the operator to be present.

The project follows a cyclic method in order to force the work forward without worrying about missing information. There were three cycles with different aim. In the first cycle, the focus was on planning the project and mapping the current state. In the second, a requirement specification was made and concepts were created. These concepts were further developed in the third cycle. Finally a recommendation was made.

The current state was mapped using different methods like interviews and spaghetti diagram. These methods showed that the lathes were unused mainly during setups, and that setups were time consuming due to equipment being placed far away from the lathes. The result showed that many problems could be related to bad layout design and lack of standardized work. In order to create a better layout for the operators, a relationship chart was made and several suggestions constructed based on it. The purpose of the layout changes was to get necessary equipment closer to the lathes in order for the setups to be performed faster. All suggestions were compared to the requirement specification and only three were further developed during the third cycle.

The lean tool SMED (Single Minute Exchange of Die) was used to create a standard for setups. This standard was further developed into a work instruction to be better visualized for the operators.

The final recommendation is to make layout changes according to one of the layouts presented in this report, and to implement the work instruction. These changes will increase the utilization by preparing as much as possible before the lathe is tuned off.

Keywords: Epiroc, layout change, work instruction, setup, SMED, production, efficiency, utilization.

CONTENTS

1

Introduction ... 1

1.1 Background ... 1

1.2 Project objectives and aims ... 1

1.3 Research questions... 2

1.4 Project scope ... 2

2 Theory ... 3

2.1 lean production ... 3

2.2 Layout types ... 4

2.2.1 Functional layout ... 4

2.2.2 Cellular layout ... 4

2.3 5S ... 4

2.4 Restoring mechanisms ... 5

2.5 SETUP ... 6

2.6 Standardized work ... 6

2.7 Work instructions ... 7

3 Method ... 8

3.1 Project planning... 8

3.2 Litterature review ... 9

3.3 Mapping and analysis of current state ... 9

3.3.1 Interviews ... 9

3.3.2 Observation ... 10

3.3.3 HTA- hierarchical task analysis ... 10

3.3.4 spaghetti diagram ... 10

3.3.5 SMED- single minute exchange of die ... 10

3.4 Requirement specification ... 11

3.5 Concept development ... 12

3.5.1 Layouts ... 12

3.5.2 Work standard ... 13

3.6 Detailed design ... 13

3.6.1 Layout ... 13

3.6.2 Work instruction ... 13

4 Current state ... 14

4.3 Organization and performance ... 17

5 Future plans ... 20

5.1 New lathes ... 20

5.2 Central washing and tumbling station ... 20

6 Requirement specification ... 21

7 Development of layout concepts ... 23

7.1 Relationship chart... 23

7.2 Workshop ... 25

7.3 Concepts and weighting ... 26

7.4 Detailed design of concepts ... 28

8 Work instructions ... 32

8.1 SMED ... 32

8.2 Standardization ... 32

8.3 Visualization ... 33

9 Discussion and analysis ... 35

9.1 Method ... 36

9.2 Results ... 36

9.2.1 layout ... 36

9.2.2 Work instruction ... 38

10 Recomendation ... 40

11 References ... 41

12 Appendices ... 42

1 INTRODUCTION

This master thesis is done as the last part of the master program in industrial design engineering, with focus on production design, at Luleå University of Technology during the spring of 2021. The project extends over 20 weeks of fulltime work, corresponding to 30 credits, starting in January. This project is done in collaboration with Epiroc with the aim of increasing the efficiency in a part of one of their workshops.

1.1 BACKGROUND

Epiroc is a leading global productivity partner for mining and infrastructure industries. They develop and produce drill rigs, rock excavation, construction equipment tools for surface and underground applications (Epiroc, 2021). They are also providing service and aftermarket support for their products.

The company was founded in Stockholm, and now has customers all around the world. Epiroc is built up by several organizations with different focus areas. Master Thesis is made in collaboration with Epiroc Rock Drills AB.

The rock drill department consists of one workshop that produces and assembles the rock drill, R&D, production planning and a material lab. The workshop has a group of lathes whose full capacity is not currently used. The group is called “the precision group” and it consists of the three lathes and two grinding machines. The reason why they are not always used is due to short operation times meaning operators do not have time to perform additional tasks the while the machines are processing. This is a problem because there is unused capacity in the workshop, and it leads to delays.

The drill department has put up a set of goals that they are aiming to reach within five years. One of them refers to increasing the productivity in everything they do by at least 25 % before year 2025.

This work has barely started yet and there is almost no data collected in order to measure the productivity at this point. Therefore, this thesis will be a part of reaching their goals and will start mapping and increasing productivity of the mentioned lathes.

1.2 PROJECT OBJECTIVES AND AIMS

The purpose of this master thesis project is to investigate how to make the processes more efficient in the precision group. The main problem is that the machines can only operate for a few minutes without the operator present, which leaves them unused when operators need to do other tasks. By examining the area and coming up with solutions that will make the situation better, Epiroc hopes to increase the utilization of the machines.

The machine operators will be directly affected by the proposed solutions since they are the ones

working with them every day. A more effective process might lower the lead time, meaning the

assembly line will get ordered articles faster. Epiroc in general will also profit from a solution to the

problem since they can save money by running the machines more. It is later up to Epiroc if they are

interested in implementing the suggested solutions or not.

1.3 RESEARCH QUESTIONS

Due to the short operation times which leave the machines unused several times a day, Epiroc wants to find ways to increase the utilization. This thesis project will therefore investigate how to make the production more efficient and how to increase the utilization within the precision group. The

questions are:

 What is the current state and which areas are most beneficial to improve?

 What can be done in order to increase the utilization of the machines?

 What can be done in order to increase the utilization of the operators?

1.4 PROJECT SCOPE

This project will only focus on the three lathes in the precision group and the tasks their operators are expected to perform. Other parts of the workshop can be included if necessary, but the initial mission is to focus on the tasks performed within the precision group. A project regarding material handling is going on parallel to this thesis, therefore problems regarding material handling won’t be investigated.

There is a plan to replace the lathes within a period of five years. That means that the solution

proposed in this project must be flexible to move somewhere else in the workshop in the future, or

have a short payback time.

2 THEORY

This chapter includes all findings from the literature study that has been used during the project. The findings are supposed to be a support for the following concepts and the recommendation.

2.1 LEAN PRODUCTION

Lean production is a philosophy based on theories from Toyotas production system (TPS) (Bellgran &

Säfsten, 2005) and has become one of the most popular paradigms in waste elimination in the manufacturing industry (Balamurugan, Kirubagharan & Ramesh, 2020). A central concept in the lean philosophy is wastes, which is everything that does not add value to the product, and the philosophy strives towards eliminating all wastes in the production. A value adding production step is something that increases the value of the product or refines the product in a way that the costumer is willing to pay for. Anything other than the minimum amount of equipment, tools and material that is vital for the production must therefore be eliminated or reduced. There are seven categories of wastes created within the lean philosophy: Overproduction, waiting time, unnecessary motion,

transportation, processing, inventory and defects. Liker (2004) later added one more category which is non-utilized talent.

A way of working according to Toyotas theories are described by Liker (2004) in 14 principles, the ones relevant for this project are listed and described below.

Principle 1: Base your management decisions on a long term philosophy, even at the expense of short-term financial goals.

The meaning of this principle is to work, grow and align the whole organization towards a common purpose that is bigger than making money. The historical place of the organization needs to be understood in order for the company to be brought to the next level. This principle will lay the foundation for all the other principles.

Principle 4: Level out the workload. (“Work as the tortoise, not like the hare”).

The elimination of wastes are just one third of the equation for making lean successful. To stop overloading people, equipment and unevenness in the production is just as important. It is therefore important to level out the workload of all manufacturing processes instead of having a start/stop approach while working.

Principle 6: Standardized tasks are the foundation for continuous improvement and employee empowerment.

Use stable, repetitive methods throughout the whole process to ensure predictability, regular timing and regular output. This can be done by collecting the accumulated knowledge about the process by standardizing the tasks according to today’s best practices. Then allow creative and individual

expression to constantly improve the standard. Also, incorporate this into the new standard so that it is easy to pass on the knowledge to the next person when moving on.

Principle 7: Use visual control so no problems are hidden.

Use simple, visual symbols to help people immediately see if they are working according to standard

or not. Also, reduce reports to one piece of paper whenever possible, even for very important

information.

Principle 12: Go and see for yourself to thoroughly understand the situation.

Go to the source yourself to observe or verify data rather than theorizing on the basis of what others have said while solving a problem. Always speak on personally verified data.

It is fully possible to follow some TPS-tools and a few of these principles, but that will only benefit in the short term since no lasting production increases will be maintained (Liker, 2004). An organization that, on the other hand, follows the TPS-tools and these principles will be able to accomplish

competitive advantages.

2.2 LAYOUT TYPES

There are several layout types used in production systems. Those that fit this project are described below.

2.2.1 F UNCTIONAL LAYOUT

In a functional layout, machines with similar functions are placed together (Bellgran & Säfsten, 2005).

For example, all lathes are grouped in one part of the workshop and the mills in another. This type of layout is often used in industries where many different products are produced in small batches. The processed product moves from one group to another depending on its processing steps. This means that the layout is flexible to produce lots of different products. The machines in each group can be operated by one operator per machine or by one operator managing several machines.

2.2.2 C ELLULAR LAYOUT

In a cellular layout, the machines are placed based on the production steps of a product (Bellgran &

Säfsten, 2005). Instead of grouping machines with similar functions together, different types of machines are grouped to be able to produce similar products. This makes the production product- oriented instead of process-oriented as the functional layout is. A cellular layout is often used when many different products are produced in large batches or for products with long lead times.

2.3 5S

A common problem in many workplaces are lack of order (Garmer, 2015). A lot of time goes to seeking material, tools and drawings that are sometimes hard to find. The lack of order could also become a safety risk. 5S is a Japanese method frequently used within lean production, which aims to create and maintain order in the workplace (5S today, n.d). The method consists of five categories;

Sort, Set in order, shine, standardize and sustain. If used properly the results are time saving, increased efficiency and a safer work environment. Here is a short description of the five categories:

Sort- The aim of this step is to remove all unnecessary equipment in the workplace by going through

every tool, furniture, material etc. (Garmer, 2015). Things that aren’t used or are used infrequently

will be removed to reduce the risk of them being in the way or taking up space. This also makes it

easier to find things when they are needed.

Set in order- After sorting there has to be structure. In 5S that means that everything has to have its

own place and it must be clear where everything belongs (Garmer, 2015). This can easily be done by marking equipment, using shadow boards and making markings on the floor where, for example, material should be placed. This makes it easier to find things and to see if something is missing.

Shine- In 5S it is everyone’s responsibility to clean up their workplace, putting away tools and

materials etc., on a daily basis. A clean workplace makes it easier to discover errors early in the process and therefore contributes to higher efficiency (5S today, n.d).

Standardize- In the beginning of the 5S implementation, companies usually find it easy to clean and

get organized (5S today, n.d). But with time, things tend to go back to the way they were.

Standardizing will systemize all new things that are implemented in order for them to be a natural part of the work process. This can be done by making check lists, creating schedules and visualizing work instructions.

Sustain- This step refers to the process of keeping 5S running and keeping everyone involved in the

process. A great way to accomplish this is to have scheduled meetings every day or week where the employees have time to discuss problems and work with continuous improvements (Garmer, 2015).

2.4 RESTORING MECHANISMS

It can be hard to change an organization through a strategic plan since organizations are slow by nature (Abrahamsson, Begntsso, Gremyr, Kowalowski, Lindahl, Nilsson, Rehn, Segerstedt, Safsten &

Öhman, 2016). The stability that forms the basis of an organization is built on an organized structure, culture and power relations. A large change that challenges these structures will most likely meet resistance of some kind. The change projects therefore rarely go as planned and the organization often goes back to the initial state at the end of the implementation, or shortly after. This

phenomena is called “restoring mechanisms” and refers to actions, conscious and unconscious, that organizations do to restore the order after a change.

Abrahamsson et al (2015) describes that restoring mechanisms can occur when the management decides on organizational change without anchoring their decision with the rest of the organization.

Management might think a certain change looks good in theory, but are not willing to put in the necessary work to restructure the organization accordingly. There can be a separation between what the organization officially communicates and what it actually does. Any employee who does not understand what is changing and why, will unwittingly resist that change since it will move them out of their comfort zone. This can eventually result in the intended change happening anyway, since it takes time for an organization to adapt a new theory, but it can also lead to a permanent change back to the previous organization. Even though the restoring mechanisms can fade away after a while, they cause unnecessary and expensive delays when they take place.

Changes initiated by the top management might lack ground in reality and therefore not be well

thought out. This can for example be because of conflicting content in management models, and the

fact that these aren’t discussed before implementation. An organizational change that is beneficial

from the managers point of view, can contribute to worse working conditions for some groups within

the organization (Abrahamsson et al, 2016). In these cases restoring mechanisms and resistance is

rational and might even prevent bad outcome.

According to Abrahamsson et al (2016), restoring mechanisms can be prevented from kicking in by being transparent and inclusive throughout the whole process. But it is also important to have in mind that some of the resistance might be rational.

2.5 SETUP

Setup is the converting from one process to another, for example changing tools and CNC program in order to produce a different part (Bhade & Hegde, 2020). The time needed to perform a setup is called setup time, and measures from the last processed part in one order to the first finished part in the next. During this time, the machine that is set up is turned off and do not produce any parts, making the setup a non-value adding step that according to lean has to be removed or at least reduced. Many or long setups contributes to production loss since the machines cannot operate during this time. But according to Gungor & Evans (2017), companies seem to be unaware of the cost related to setups even though lots of the losses in manufacturing industries can be attributed to these.

Today’s demands often require the production to be flexible and customizable, companies therefore choose to manufacture in small batches to keep the processes lean (Parwani & Hu, 2021). However, small batches leads to many setups and high costs. In order for small batches to be beneficial, the setup times must be reduced. Setup times can be reduced by eliminating all activities performed during setup that does not have to be done as the machines are turned off (Parwani & Hu, 2021).

This will save production time and lower costs. To make the setups even more effective, Parwani &

Hu (2021) states that the production scheduling must take setups into account. Similar tasks should be groups together to decrease the setup time, which can be done by upgrading current operating procedures.

2.6 STANDARDIZED WORK

The idea of establishing standards has long been embraced by Japanese companies and is a large part of lean production. But the view of standards in western companies are often more critical and assumed to contribute to unfair conditions for the workers (Imai, 2007), and there is a feeling that humans should be given maximum freedom to manage their jobs anyway they want. Imai (2007) says that it is important to distinguish between “controlling” and “managing”, and while talking about control, managers refer to control over the process, not over people. Standards in his view represent the best, easiest and safest way to perform a task, which also contribute to preserving know-how and experience. If the employee who knows the work the best leaves, his or her knowledge also leaves. But if standards are established, this knowledge will stay inside the company and it will also be easier to educate new employees using the best known way.

Imai (2007) also argues that there cannot be any improvements in processes if there are no standards. Because, if the process regularly changes depending on person or situation, an

improvement will only become one more version of how to perform the task. A standardized work

therefore lays the foundation for continuous improvements in an organization.

2.7 WORK INSTRUCTIONS

By standardizing work tasks it is possible to increase productivity and quality, among other things.

The implementation of a standard requires instructions that are simple to follow and easy to understand (Olofsson, 2016). Organizations often have manuals or instructions that describe how a task should be performed, and these are usually kept in folders that are stowed away and rarely used. Olofsson (2016) confirms this problem and relates it to the way the instructions are

constructed. Traditional instructions consists of long text documents that describe a task in detail, which makes them hard to follow and result in them not being used. Another common reason a ccording to Olofsson is that the instructions don’t describe the tasks as they are really performed by the workers, making them irrelevant and leaving them unused. The reason for this can either be that the workers weren’t included while creating the instructions or that the managers have a

misconception of how the work is performed. User involvement is the key to avoid this problem and to make relevant instructions. Another cause of irrelevant instructions can be that instructions are not updated as processes evolve. An instruction should, according to Olofsson (2016), be constructed according to the best known way of performing a task. And since organizations constantly change, for example by hiring new workers, purchasing new machines or by workers finding shortcuts in their work, this best way also changes. Therefore, it is important to keep the instructions updated and change them even for the smallest things.

To increase the chances that an instruction will be used, it is important to make it short (Olofsson, 2016). It should also give answers to the following questions; What to do?, How to do it?, Why should it be performed in that way?

The theory of dual coding states that a person’s working memory consists of two systems; the verbal and the nonverbal (Gellevij, Van Der Meij, De Jong & Pieters, 2002), where the verbal can be seen as text and the nonverbal as pictures. According to the theory, more learning occurs when these two are combined because of the way the person processes the information in his or her working memory. By using both of these systems it is possible to process more information compared to using only one of them. But the working memory is limited and too much additional information may have a negative effect. It is therefore vital to find the right balance between text and pictures.

In the early 1900s Max Wertheimer, Wolfgang Köhler and Kurt Koffka founded the Gestalt

psychology, a theory that describes the human perception (Nationalencyklopedin, n.d). They stated that experiences are characterized by the organizing of elements and that the whole is greater than the sum of its parts. The Gestalt psychology created gestalt laws based on their theories, and these laws are still used today. Three of them are described below:

A- Proximity between the elements make them appear grouped vertically in Figure 1.

B- Similarities between elements will make them appear grouped horizontally in the figure.

C- Our vision creates continuous patterns and perceives connected objects as uninterrupted.

The brain will therefore see figure C as one circle and one rectangle, not as the figures in D.

3 METHOD

The structure of the project follows the project cycle by Ranhagen (1995). The method is based on an iterative process built up by three cycles with different focus areas which force the project forward and keeps it from getting stuck in a single phase. The first cycle focuses mainly on planning the project, mapping the current state of the production and organization, and defining the main goals and scope of the future work. For the second cycle the focus has shifted and the work revolves around creating a requirement specification and finding solutions to the problems found in cycle one.

This will be done by analyzing the results from the mapping and investigating the factors causing the current state problems. These solutions will be further developed during the third cycle, where the focus lies on evaluating the solutions according to the requirements and construct complete solutions that can be implemented.

Even though the focus is different through the cycles, there is always room for reprocessing of previous phases. In that way, the project can be forced forward without worrying about missing important information.

3.1 PROJECT PLANNING

Early in the project a rough plan was put together in order to structure and organize the future work, see table 1. This plan includes the three cycles and visualizes the different focus areas in each cycle.

There are also some deadlines in the plan marking the dates of presentation and report hand in.

TABLE 1. PROJECT PLAN

3.2 LITTERATURE REVIEW

The literature review forms the basis for this project by gathering information and theories that will be used while forming the results. A lot of the theory was found in books, and scientific data bases like Web of science and Scopus. The keywords used were different combinations of “Layout”,

“Production”, “work instruction”, “standard” and “setup”.

The search started by looking up theory from similar projects, which were found using google scholar. The parts that were relevant for this project were further investigated and the sources for those parts were looked up.

3.3 MAPPING AND ANALYSIS OF CURRENT STATE

The mapping of the production was done mostly in the beginning of the project. The goal during this part of the process was to collect as much information about the production as possible in order to get a foundation to start from.

3.3.1 I ^NTERVIEWS

There are different types of interviews, the two used in this report are described below.

U

An unstructured interview consists of open questions that can be answered freely by the interviewee (Karlsson, Osvalder & Rose, 2015). The questions can, but do not have to be constructed in advance.

This makes it easier for the interviewer to gain information about things that are not asked for.

Unstructured interviews have been used a lot in this project to get information about the processes and current problems. A majority of the unstructured interviews have been conducted with the operators, and some of them with other employees like the flow manager or the production engineer. In the first weeks, during the mapping and understanding of the process, these kinds of questions were asked every day.

S

When there are some prepared questions but still room for the interviewee to answer freely, the type of interview is called semi structured (Karlsson, Osvalder & Rose, 2015). This kind has been used during booked meetings where a specific topic has been discussed.

Four meetings, each one hour long, have been held with the operators. These meetings have been

used for giving them information about the project, performing a layout workshop and doing the

SMED analysis. There have also been two meetings with a maintenance technician, and two meetings

with the flow manager and production engineer.

3.3.2 O BSERVATION

Observations have been made continuously during the project, mainly in the workshop, but also by reading documents and studying collected data. These observations have been combined with unstructured interviews in order to get as much information as possible and understand the tasks.

The gathered information has been documented in photos, videos and by taking notes.

3.3.3 HTA- HIERARCHICAL TASK ANALYSIS

The hierarchical task analysis is a method used to structure and understand how a task is performed by documenting all the steps an operator goes through in order to complete the task (Karlsson, Osvalder & Rose, 2015). The information needed is gathered through observations and interviews with the operators, and by reading manuals and task descriptions.

The analysis starts by identifying the main goal or purpose for the task. The goal is then divided into part-goals which are steps that need to be completed in order to reach the main goal. These part- goals are then divided into smaller steps until there are no steps left. The results are collected and presented in a tree-diagram where the main goal is on top and the part-goals are spread downwards.

The HTA has mainly been used during the mapping of the current state, in order to understand every step in the process and making sure to not miss important work tasks. The information has been collected by observation and unstructured interviews.

3.3.4 SPAGHETTI DIAGRAM

A spaghetti diagram is a visual presentation of how people and material move through a process (What is six sigma, n.d). The method is part of the lean tools and aims to reduce wastes through transportation, waiting times and motion. The diagram is drawn using a paper showing the factory layout and a pen. The operators or material is observed and all motions are drawn down on the paper. The result is a layout full of lines showing where the operator needs to move to complete their tasks. This is then helpful when reorganizing the layout or finding important functions in the system.

The method has been used in this project to understand where important functions such as tools, materials and equipment is located and how often the operators need to get to them. All studies made have started in the end of one order and ended when the machine is running normally. This is because the times for one order can be several hours and the main work during this time is moving pieces in and out of the machine. By starting at the end it was possible to see the important steps without having to spend the whole day with the same operator.

3.3.5 SMED- SINGLE MINUTE EXCHANGE OF DIE

There are lots of tools in lean meant to reduce wastes, SMED is one of them and it focuses on setup- times (Bhade & Hegde, 2020). The time required to change production setup from the current product to another is called changeover time or setup time, and is considered a waste since the changing does not add value to the product. The machine cannot work during the setup and

therefore this time has to be reduced as much as possible. The SMED tool strives to reduce this time

by dividing the setup into two categories: internal and external processes. Internal processes include

everything that must be done while the machine is turned off and can only be performed when the

machine has finished its previous operation, while external processes are tasks that can be made in advance as the machine is still running.

The method starts with classifying every step of the setup process to either be an external or internal process. This is done by studying the current state of how the setups are performed. The next step is to look into the internal steps to see if there are processes currently marked as internal that could be converted to external. Gathering tools, cleaning and product handling for example might be done during the setup as an internal process even though they could be made external (Bhade & Hegde, 2020). In order for the new setup routine to be as efficient as possible it is important to locate necessary tools and equipment close to the operating areas so that the setup can be performed quickly.

SMED has been used in this project to analyze the setups and classify all steps required to perform them. This was done by filming the operators in each machine during a setup and later writing down every step they made and marking them as either internal or external. The results from this first step were shown to the operators in order for them to convert as many of the internal processes as possible to external. According to the operators there was not enough time to make preparations due to the short processing times, therefore they hardly converted any of the steps to external.

To confirm this, another classification was done together with the flow manager and the production engineer who did not share the operators’ opinions. They thought that only the steps being done inside the machines should be labeled as internal. Even though some articles have an operation time too short for preparations to be made while it’s working, there is always time to perform some preparations. The analysis therefore continued with the classification done together with the flow manager and the production engineer.

3.4 REQUIREMENT SPECIFICATION

The requirement specification for the layout was constructed during the second cycle together with the supervisor at Epiroc. The specification is based on input and restrictions from the flow manager and the supervisor, for example the amount of employees in the group and available space.

A paired comparison of all the requirements were made once the specification was done. Every requirement was compared with every other requirement as a pair, where the more important of the two received a score of 1, while the other one got 0. The scores for every requirement was then added, and the ones with the highest total score could be seen as most important. The requirements were then categorized into three groups based on their total score. A total of 7-10 points was

considered “very important”, 4-6 points “important” and 0-3 points “less important”. The groups each got a weight of 7, 6 and 5 in order to make a weighted scoring model.

The weighted scoring model was used to rank the layout suggestions in order to find the one that best met the requirements. Depending on how well the layout met the requirements it was assigned with a score, 3 if “Fully meets the requirement”, 2 if “Acceptable”, 1 if “partially meets the

requirements” and 0 if “does not meet requirement”. Every layout suggestion was given one of these scores for every requirement in the specification. The score was then multiplied with the weighing done previously and the total score for every layout was counted by adding every requirement score.

By comparing the layout score to the highest possible score (if all requirements were fully met) a

percentage of how good the layout was could be calculated.

This method helped ranking the layouts by comparing how well they met the requirements. Those who did not meet the requirements well enough were chosen to not proceed into future work.

3.5 CONCEPT DEVELOPMENT

This chapter describes the development of concepts made during the second cycle.

3.5.1 L AYOUTS

The layout process began by making a simplified version of the relationship chart, described by Muther and Hales (2015). This chart is part of a larger method used to arrange layouts. The purpose of the method was to rearrange the workplace by locating areas and equipment with high frequency and relation close to each other. Every function, surface and activity was listed and the importance of relative closeness required between each pair was specified. There were five different relations used, which are described in table 2. This step was based on the spaghetti diagram made during the first cycle which showed what tings the operators use frequently and what things are used in combination with each other. The operators were also asked about their experiences and how they would prefer the relations to be.

TABLE 2.THE DIFFERENT RELATIONS USED IN THE SYSTEMATIC LAYOUT PLANNING. Color Relation Description

Absolutely necessary This relation is given to things that has to be located very close, within 1.5m from each other.

Especially important When it is desirable to have things close, they are given this relation. The location should be within 3m.

Important If a task favors from two things being close, within 6m, this relation is given.

Unimportant This relation is given if there is no need for two things to be close.

Not desirable This relation if given if two things should be separated.

The layout suggestions were later constructed using an AutoCAD drawing of the workshop, without any machines or equipment. The machines were placed on the empty workshop drawing first, since their placement is most important due to their size. After that, the equipment as placed according to the relationship chart beginning with the items with highest demands. This process was repeated with several machine placements to generate multiple suggestions for layouts. Seven different layout suggestions were made and these were weighted and ranked according to the requirement

specifications.

L

In order to get the operators thoughts on layout and to hear their ideas, a workshop was held. A

drawing of all equipment used in the workshop was printed on a piece of paper and cut out. The

operators were then asked to build their “dream layout” by moving the pieces to their ideal position.

This was done two times with different aims. During the first try there were no boundaries and the operators only had to build the layout closest to their lathe. The purpose for this was the see how they would place the most vital equipment if they had unlimited space. During the second try, the pieces had to be placed within the current area. This was visualized using a print of the workshop without any equipment. This time they also had to fit in the rest of the equipment and show how they wanted the relations to be between all functions in the group. This made it easier to understand how the operators wanted their layout and what equipment they need to perform their tasks. It also contributed to the operators understanding how difficult it is to rearrange the layout, which made it easier for them to accept the proposed suggestions.

The result from this exercise was considered during the creation of layout suggestions.

3.5.2 W ORK STANDARD

A work standard was created based on the results from the SMED analysis in order to decide in what order the tasks during a setup should be performed. The purpose of this was making a standard that would contribute to using time in the most efficient way by preparing as much as possible before turning the lathes off. The standard was shown to the flow manager and the production engineer, who gave their comments.

3.6 DETAILED DESIGN

The third cycle consisted of further developing the concepts created in cycle two. The development process is described in this chapter.

3.6.1 L ^AYOUT

The three layout suggestions with the highest percentage ranking from the weighted scoring model were chosen to continue working with. The reason for this was to have suggestions within different price ranges, since the requirement regarding price was not considered in the weighting process.

Details in the suggestions were modified to get even better suggestions. This was made based on feedback from engineers and a maintenance technician and mostly regarded changes required for the layouts to be possible to implement.

The suggestions were later shown to a maintenance technician again to ensure the layouts would be possible to implement. This person also gave rough cost estimates for each suggestion based on experience.

3.6.2 W ORK INSTRUCTION

The work standard created during the second cycle was developed further into a work instruction.

The purpose was to visualize the standard in a way that would be easy to understand, for both

experienced and new operators. To accomplish this, it was based on theories about gestalt laws

described in chapter 2. Three different designs were created and later shown to the operators, the

flow manager and the production engineer. Since the three suggestions were totally different, they

gave feedback on what they liked and didn’t for each of them. Their comments were considered

4 CURRENT STATE

These are the results from the mapping phase, describing the processes used today.

4.1 THE PRECISION GROUP

The workshop is divided into three main parts; the small cylinder flow, housing and the assembly line. The small cylinder flow manufactures round components mounted inside the housing, which is done in the assembly line. This thesis work is limited to the small cylinder flow (marked with yellow in Figure 2), more specifically to the three lathes located in the precision group (marked with purple in Figure 2). Besides the lathes there is one washer, one tumbling machine and two grinding

machines, one of which is rarely used because of its old age. The layout of the precision group is further described in Figure 3.

F^IGURE 2.THE YELLOW MARKING SHOWS THE SMALL CYLINDER FLOW, THE PURPLE AREA IS THE PRECISION GROUP AND THE MATERIAL HANDLING AREA IS MARKED IN GREEN.THE RED X-MAKINGS SHOWS WHERE THE FORKLIFTS ARE LOCATED. FOR SECRECY REASONS, MOST PARTS OF THE LAYOUT ARE HIDDEN.

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FIGURE 3. THE MACHINES LOCATED IN THE PRECISION GROUP.THE COLORS SHOW WHERE MATERIAL (BLUE), TOOLS (GREEN) AND SHARED EQUIPMENT

(^YELLOW) ARE LOCATED.

Common for all machines in the small cylinder flow is that they manufacture round parts, mainly by turning. The machines are specialized for specific areas meaning one article doesn’t go through all of them, only the ones needed for the specific part. There is one exception though, almost all parts are processed in the precision group as their final step. This is because the precision group is specialized in refining surfaces with small tolerances, which is an important last step for almost all parts due to the fine tolerances in the drill. Both the lathes and the grinding machine are used for the same purpose, but some articles are easier to process in the grinding machine and vice versa.

There are seven operators working within the precision group during three shifts. During the first shift there are three operators operating the three lathes. During the second shift there are two operators operating two of the lathes and one operating the grinding machine. The third shift (night) consists of only one operator who works with the most urgent orders, meaning this operator can manage all the machines but chooses which one or ones to use. Although the operators manage one machine each, they share the washer and the tumbling machine within the group.

4.2 PROCESS AND FLOW

A majority of the articles processed in the precision group are at their last processing step before storage. Before coming here they might have been through several other steps in other parts of the small cylinder flow. The finished parts are either sold as spare parts or placed in a storage in order to be used in the assembly line. Since this is the last step before assembly or before being sold it is important that all parts are washed and packaged.

The process usually consists of these steps: Getting material, machine set-up, machining, tumbling (not all articles), washing, packaging and lastly, transporting the finished parts to the material handling area.

LATHE 22 GRINDER

New

LATHE 21

LATHE 23

WASHER GRINDER

Old

TUMBLER

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The operators need to move their material at least two times during one order. The first time to get the material to their machines, and the second time to transport finished parts to the material handling area. The material is transported to the precision group by the material-handlers, who place the pallets in one of the racks located next to the forklift aisle. Very often, there are too few pallet racks in the precision group to fit all materials, and pallets are then placed in racks further away. The material is usually delivered long before it is needed in the machines and it is later up to the

operators to lift it down and move it to the machines. In order to lift the material down, the

operators need to use a forklift. There are two available forklifts and those are used by several other production groups and located according to Figure 2. Due to the location of the forklifts and the fact that they are also used by other operators, it can take a long time to get a forklift and to perform the material handling task.

When an order is finished it is up to the operators to transport the pallet to the material handling area. This is also done by using a forklift, the only difference is the long distance to the material handling area, see Figure 2. The material handling is, over all, a very time consuming task to perform.

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There are approximately 150 different articles processed in each of the lathes and every time a new order starts the operators have to make a changeover which means converting from one process to another. Every lathe undergoes around three setups every shift. The setup time can vary depending on what equipment needs to be changed. A large setup can take up to 45 minutes and consists of changing a majority of the tools, turning inserts and clamping. While a smaller setup usually only changes some of the tools and can be completed faster. Every time a tool or turning insert is changed it has to be measured to ensure it is fitted correctly.

The setup process starts by collecting the required tools, these are listed on the order card that is printed out by the operators before the setup begins. It is also possible to see exactly where these tools are stored in order for the operators to find them easier. Every lathe has its own cabinets with equipment where almost everything is stored. In some cases, equipment has to be borrowed from one of the other lathes because there is only one and it is shared by several parts of the group. There are also some equipment, for example chuck and hydraulic fixtures that are stored in trolleys since they do not fit in the cabinets.

The operator usually starts with changing tools and turning inserts, after that is done they start changing the clamps. There are several ways to change the clamping, either the whole chuck is replaced or only the clamping jaws.

When everything is changed and measured in the machine it is time to process the first part. This is done slowly and the operator measures the part to ensure the setup was successful. The

measurements are rarely perfect at the first try, and the operator has to adjust the tool offset until the measurements comply with the drawing.

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The processing of the parts can start when the setup is complete and the measurements are right.

Inserting the material in the lathes is done manually by the operator, and only one part is processed at a time. For some articles, where accuracy is very important, the operator needs to use an indicator while attaching the part in order to make sure it is not skewed.

When the processing is done the parts are either measured while still in the machine or taken out to

be measured on the measuring table.

When processing is complete the part is taken out of the machine and another one is inserted. The processed part is measured and deburred by the operator. There is an exception for some parts that have to be measured while still in the machine, due to stresses in the material that will cause deformations when detached. There are also some parts that are measured in the measuring room by specialized measurement staff.

The finished parts are either placed back in the pallet, on a trolley or in a wash basket, depending on the next step.

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Tumbling is a deburring method where rocks are used to smoothen and deburr surfaces, but it is not used for all articles in the precision group. Articles that aren’t tumbled instead go directly to washing.

When enough articles are gathered that need to be tumbled, they are put on a trolley and taken to the tumbler. The number of parts that fit in the tumbler depend on their size. They run a cycle of 15 minutes, after which they are put in a wash basket and taken to the washer. The cycle is autonomous and does not require monitoring.

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All parts produced by the precision group have to be washed, especially after tumbling since the process leaves a film on the components, making them sensitive to rust. The machined parts are often placed directly in the wash basket, which is later taken to the washer. The basket is placed in the washer and a door is closed. This machine is also autonomous and does not require monitoring.

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There are several ways to pack the articles before transporting them to the material handling area.

The way of packing depends on the article and where it will go next. Most parts are just put in a pallet to later be stored and used in the assembly, they either use the same pallet as the material arrived in or a half pallet. The half pallet is stored on the other side of the forklift aisle and the operator needs to get it by hand. Very fragile parts are places in soft tubes for protection before being placed in pallets. The packaging is performed by the operators and later transported to the material handling area.

4.3 ORGANIZATION AND PERFORMANCE

The person responsible for the outcome in the precision group, and the small cylinder flow as a whole, is called the flow manager. He has the overall responsibility for all operators in the flow.

There is also a production engineer that only works towards the precision group, his job is to support the operators in technical issues, for example by making CNC programs and buying new tools when needed.

The shifts overlap by 12 minutes, during this time the operators are supposed to share important

information about the production to each other. During this time, the flow manager holds a short

meeting to inform the operators about current production.

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Spaghetti diagrams were made during the mapping of the production and the results showed that the layout contributed to lots of movement and long transportations. The diagrams can be seen in appendix 1. Even though the three laths are very similar to each other and requires the same operation steps, the location of and distance to vital equipment is not the same. The longest movements and transportation that is performed by the operators are connected to the handling of material, due to the location of the forklifts and the long distance to the material handling area where all finished products are taken. This is time consuming and is often done while the machine is stopped due to setup.

Every lathe has its own cabinets with tools, turning insets, clamps and some frequently used

measuring tools. For lathe 21, these cabinets are located within the lathe operating area which make them easy for the operator to access. But for the other two lathes the cabinets are separated from the area. Operating area refers to the area right in front of the lathe from where the operator operates the machine.

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While following the operators during the spaghetti diagrams it was clear that everyone preformed the work tasks differently. It could be by doing the steps in a different order or having own tricks to manage the tasks. According to the operators there are no work descriptions or standardized tasks, everyone manages their own work as they like. This contributes to ineffective work because some operators have more effective ways to perform their tasks than others. For example the operator in lathe 21 prepares the coming setup by collecting all required equipment on a trolley and bringing them to the machine as the machine is processing. The operator in late 23, on the other hand, waits until the machine has stopped before getting the equipment and doing it by collecting one at a time which can be seen in appendix 1.

While talking to the operators about the setups and asking them why they do not prepare more, they answer that the processing times are so short that there are no time for preparations. Even if they have time for preparations, they don’t have the space to fit equipment for upcoming setups close to their machines. A lot of the equipment is stored on trolleys that have to be transported to the front of the lathe during set up. Even if there was time to do this as a preparation, it would most likely be in the way of the operator or block walking paths for other operators. This is according to the operators.

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The area allocated to the precision group is small, which in some places result in narrow passages

and a lack of space for equipment as described above. If you look at the drawing of the layout (Figure

3), it seems to work well, but in reality there is more material and equipment that is not visualized in

the layout. Among other things, operators in 23 and 22 need pallet trolleys to be able to transport

material to the lathes. In order to be able to work as efficiently as possible, at least two such trolleys

are needed for each lathe for the operators to be able to prepare materials. However, there is no

place for these trolleys in their area and they are placed wherever. This leads to unnecessary

problems as they often stand in the way for operators. The same problem occurs with the shavings

containers, which are sometimes placed where operators need to walk. However, these containers

have marked places where they are supposed to stand while not being used, but there are too few

places for the amount of containers needed. Two examples are shown in Figure 4 and 5.

5S is an established method in the group when it comes to cleaning and replacing used equipment.

But they do not utilize the method beyond cleaning and replacing equipment. If 5S was used in its entirety, every piece of equipment, all the tools and materials should have had assigned places in the area.

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The lack of standardized tasks contribute to a tension between the operators, especially between shift partners (those who use the same lathe but on different shifts) which makes it harder to collaborate within the team. For example, if one operator always starts preparing for an upcoming task before it needs to be performed, he would most likely want his shift partner to do the same so that he can work according to his routine regardless of who’s been managing the machine before him. But this is not done within the precision group since everyone works by their own routines, making it harder to resume work started by someone else.

F^IGURE 4.TWO OF THE CONTAINERS ARE PLACED INSIDE OF THE MARKINGS,

WHICH ARE BARELY VISIBLE.THE CONTAINER IN THE BACK DOESN’T FIT IN THE MARKED AREA AND IS THEREFORE LEFT IN FRONT OF THE ENTRANCE. FIGURE 5.THE PICTURE SHOWS ONE ENTRANCE WHERE THE WAY IS BLOCKED BY

ONE CONTAINER AND ONE PALLET TROLLEY.

5 FUTURE PLANS

There are continually projects going on which aim to make changes and continuous improvements in the workshop. Some of these projects may affect the precision group and the improvements

resulting from this thesis work. Therefore it might be good to have some of these future plans in mind while making suggestions for the precision group. Some plans are described below.

5.1 NEW LATHES

The lathes in the precision group are very old and soon it will be time to replace them with new ones.

The project in which these investments are discussed will take at least 6 months to finish, and after one lathe is ordered there will be a delivery time of one year. The process of buying and installing a new machine will therefore take 1.5 years as minimum. The lathes won’t be purchased all at once, meaning it will take much longer to replace all of them. It is not decided when this project will start, some say 2022 while others think 2024. The reason for this is the investment plan has been put on hold due to a decision that prevented them from making any investments during the past year.

Therefore there are some other machines in the workshop that are in worse condition than those in the precision group, which will probably be replaced first.

Once the project starts, lathe 21 will be the first one to be replaced. The plan is to buy a larger machine that is a combination of a lathe and a grinding machine in order to replace both the lathe and the old grinder with this new one. The next investment in the group will be a replacement for lathe 22, followed by lathe 23. These lathes will be replaced with machines similar to those who are used today. The size of them will be nearly the same and the same articles are planned to be produced in them.

5.2 CENTRAL WASHING AND TUMBLING STATION

At the moment there are lots of washing machines and tumbling machines in the workshop. In order to be more efficient and increase the quality of washing and tumbling on finished parts, there are plans of creating a central washing station. The purpose of having a shared space for these operations would be to reduce the amount of work performed by the operators in the lathes and increase the quality by hiring new staff that would only focus on washing and tumbling. The project in which this is planned and discussed has recently started, and it will therefore take years before implementation.

It is not decided whether this plan will become reality, since the work has recently started. But the

plans for now are to create this area near the precision group, on the other side of the forklift aisle,

see Figure 2.

6 REQUIREMENT SPECIFICATION

The following is the requirements for the new layout, constructed together with the supervisor at Epiroc.

1. Economically sound

The layout changes shall be economically sound.

2. Compatible with today’s tasks

The new layout must be adapted to the tasks that are done today, except for the assembly of housings since this task will be removed anyways.

3. One operator per lathe

One operator manages one lathe and all additional tasks. There must also be one operator to manage the new grinding machine and the additional tasks. The old grinding machine does not need an operator.

4. Must fit in designated area

The same area that the precision group is assigned today will be available for the new layout, i.e. the area for the lathes, the grinders, the tumbling, the washing machine and the

assembly table.

5. Decrease the need to cross the forklift aisle

In order to decrease the risk of accidents involving forklifts, the new layout should strive to minimize the need for operators to walk across the forklift aisle.

6. Follow the relationship chart

The layout should, as far as possible, follow the relationship chart so that important functions are located near each other.

Desirable: Both the area closest to the lathes and functions with shared use follows the

relationship chart.

Acceptable: The area closest to the lathes, the operating area, follows the relationship cart.

7. Encourage 5S

All equipment that is used regularly must have an assigned and marked place to not get in the way. These locations should follow the 5S method. The precise amount of equipment necessary should be available to operators, no unnecessary spares.

8. Easy movement between functions

It must be easy for operators to access frequently used functions, for example the washing machine.

There shall be marked locations for equipment used by operators on occasion, for example

pallet trolleys and special tools to avoid equipment from being placed where other operators

need to walk.

9. Accessible for maintenance

There must be enough space to easily access the lathes for maintenance, meaning no rigidly mounted equipment shall be in the way. To allow access for the forklifts to lift the chip conveyor there must be at least 1.3 m for the forklift to fit, more if it has to turn. There must also be at least 1 m in front of the lathe to put the conveyor once taken out.

To perform electrical maintenance it has to be possible for a lift to enter the group, this requires an entrance of minimum 1.5 m. It is also desirable to have it placed under the electrical rail.

The lathes shall also be accessible from the back and the sides. In the back there must be at least 0.8 m between the lathe and its belonging cooling water tank to ensure that

maintenance staff can perform service. The sides of the lathe must be accessible to the operators at all times in order for them to perform setups. At least 1 m is required.

10. Flexibility for future change

Known future plans, like purchase of new lathes, shall be possible to include in the layout

without fundamental changes.

7 DEVELOPMENT OF LAYOUT CONCEPTS

Many of the problem areas found during the mapping phase were considered results of a bad layout which is not optimized after the operators and the work they are supposed to perform. In particular, the utilization of the lathes could be increased by decreasing the time needed for setups. But to accomplish that, it must be easier for the operators to prepare setups even though process times are short. A new layout was therefore designed as a first step of making the precision group more effective by locating necessary equipment closer to the operators.

The new layout is based on the same inventory as today, see appendix 2.

7.1 RELATIONSHIP CHART

The relationship chart shown in table 3 describes the desired relations between equipment in the

new layout. While making the chart the focus was on putting equipment needed during setup closest

to the lathes, since one of the problems discovered during the mapping phase was that barely

anyone prepares for setups in advance. The idea of rearranging like this is to save time by decreasing

the distance to vital things like tool cabinets, measuring table and material. Other things, like the

washing and tumbling machines, would benefit from being close to the lathes but doesn’t have to be,

therefore they have a yellow mark. There are also red marks in the chart that marks a relationship

that is not desirable. The whiteboard in this case has this relation to the lathes and the tumbling

machine, because the daily meetings are held in front of the whiteboard and both the lathes and

tumbling machine are very loud. It can be good to know that this relation is not the most important,

even though it might contribute to a better environment for meetings.

T^ABLE 3.THE RELATIONSHIP CHART DESCRIBING THE WANTED RELATIONS IN THE NEW LAYOUT.

Color Relation Description

Absolutely necessary This relation is given to things that has to be located very close, within 1.5m from each other.

Especially important When it is desirable to have things close, they are given this relation. The location should be within 3m.

Important If a task favors from two things being close, within 6m, this relation is given.

Unimportant This relation is given if there is no need for two things to be close.

Not desirable This relation if given if two things should be

separated.

7.2 WORKSHOP

The workshop with the operators resulted in understanding what they thought was important while making a new layout. Their ideas and wishes were similar to each other’s and corresponded well with the relationship chart. An example is shown in Figure 6.

FIGURE 6.ONE OF THE LAYOUT SUGGESTION FROM THE OPERATORS.. THE COLORS SHOW WHERE THE LATHES (RED), MATERIAL (BLUE), TOOLS (GREEN)

AND SHARED EQUIPMENT (^YELLOW) ARE PLACED.

They kept saying “we want the layout to be as it was before”, referring to the layout used in 2012, see Figure 7. The layout was rearranged to the current one due to the purchase of a new larger lathe close to the precision group. This new machine needed more space than before which led to

rearrangement and resulted in decreased space for the precision group. This led to worse working conditions, according to the operators, and they feel like many of the problems related to layout and movement mentioned in the previous chapter started then.

While investigating if it would be possible to go back to the old layout it was discovered that there is not enough space to fit the lathes. Even if the tumbling and washing machines were removed, it would be too tight. Further investigations and discussion showed that the reason for their obsession with the previous layout could be related to the disorder resulting from the rearrangement. One of the results of the previous change to the precision group, was that they needed to use pallet trolleys to transport their material to the lathes, since they were no longer placed next to the forklift aisle and a pallet rack. They describe the extra work as more time-consuming, but not as the real issue.

The real problem, and the reason why they want to get rid of the need to have pallet trolleys, is that

the space is too small to fit them in the current layout. This makes movement hard since the trolleys

frequently block the routes where operators walk around the workshop.

7.3 CONCEPTS AND WEIGHTING

Several different layout suggestions were constructed based on the relationship chart and with input from the operators. Some of them were unrealistic or even impossible to continue working with.

Therefore there were only seven suggestions considered good enough to bring to the weighing process. These can be seen in appendix 3.

The first requirement “economically sound” is hard to measure since there is no exact amount of money given to this project. The decision that will determine if the recommended layout change is affordable will be taken once this thesis work is complete. It is therefore not possible to have that requirement in the weighting process. It still has to be considered however, since there is a will to keep costs as low as possible.

All of the other requirements were included in the paired comparison, table 4. The higher the total score, the more important the requirement. The most important requirements are to have one operator per lathe and to fit the precision group in the same area used today. These are things that have to be fulfilled and they are therefore given the highest weight.

F^IGURE 7.DRAWING OF THE PREVIOUS LAYOUT WHERE EVERY LATHE WAS PLACED CLOSE TO A PALLET RACK AND NO PALLET TROLLEYS WERE NEEDED.THE RED LINES INDICATE THE AREA OF THE PRECISION GROUP TODAY.

LATHE 21

LATHE 21

LATHE 23

LATHE 23 OLD GRINDER

OLD GRINDER

WASHER

WASHER

TUMBLER R

TUMBLER R

LATHE 22

LATHE 22

Table 5 shows how well each layout suggestion fulfills the requirements. The current layout got a 57 % match in this evaluation, making all the other suggestions better according to the requirement specification.

T^ABLE 4.THE TABLE SHOWS THE PAIRED COMPARISON DONE WITH THE REQUIREMENTS.THE REQUIREMENT REGARDING ECONOMY IS NOT REPRESENTED.

APPENDIX 1

T^ABLE 5.RESULTS OF THE WEIGHTED SCORING MODEL.

TABLE5. XXXXXXXXXXXXXX