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Aniket 07.10.15

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Project on reducing delivery time at
perfect profile centre
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Table of Contents
Introduction.............................................................................................
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Executive summary
Project work is carried out at Perfect Profile Center located at Gala No.14,15,16 Parmar
industrial co...
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  1. 1. 1 Project on reducing delivery time at perfect profile centre
  2. 2. 2 Table of Contents Introduction.......................................................................................................................................5 Background........................................................................................................................................7 Profile of Organizational .....................................................................................................................9 Lead time reductions theories .....................................................................................................13 Literature Review ...........................................................................................................................22 Proposed Methodologies ...............................................................................................................26 Batching Machines ...................................................................................................................26 Machine Downtimes .................................................................................................................27 Research Methodology..................................................................................................................27 Method of analysis:........................................................................................................................29 Current state analysis ..................................................................................................................31 Data collection, Analysis and interpretation.......................................................................................32 Findings & Suggestions .....................................................................................................................35 Conclusions......................................................................................................................................38 References.....................................................................................................................................38
  3. 3. 3 Executive summary Project work is carried out at Perfect Profile Center located at Gala No.14,15,16 Parmar industrial complex, Chinchwad Pune 411019, Maharashtra India. Company is a small scale company and is involved in manufacturing of Cutting Tools and profile form cutters. In today’s competitive business world, companies require small lead times, low costs and high customer service levels to survive. Lead time is the time spent that elapses between the placement of an order and the receipt of the order into inventory, lead time may influence customer service and impact inventory costs. In today’s context, customers want timely delivery of the product and if proper delivery is given then higher customer satisfaction can be gained and results in retention of customer and growth of business. The study has been carried out to analyze causes for late delivery of the product to customers. Based on the primary and secondary data by studying the delay in delivery to the customer. The causes for the delay in the delivery are observed by studying processing time for manufacturing of the tools. The data is then analyzed with the help of line diagrams and bar charts and valued suggestions are given to the company.
  4. 4. 4 Abstract In today’s competitive business world, companies require small lead times, low costs and high customer service levels to survive. Because of this, companies have become more customers focused. The result is that companies have been putting in significant effort to reduce their lead times. The purpose of this master thesis was to reduce lead time at perfect profile centre by focusing both on ordering and production times. The study was initiated by investigating the customer needs, to give an indication of the length of the lead times accepted by the customers. The information gathered was compared to the lead times found during the chartings of the current flows of material and information. The findings were used as a basis when analyzing the current state and suggesting improvements for the future product flows. The information was gathered at Unit 1 through interviews, sales statistics documentation and production observations, along with literature studies, and value stream maps were used to visualize the bottlenecks and sources of waste in the product flows. It was found that the most appropriate mapping method for lead time reduction was Value Stream Mapping (VSM). From the results achieved by VSM it was obvious that the press machines were bottlenecks. In order to increase their capacity, their change over time should be reduced. Another observation derived from the VSM, was that a new order passing through the ordering department is an unnecessary step. Some other recommended changes based on applying TPS are:  Reduction of work in process inventory (WIP)  Reduction of waiting time between press and converter  Stop the process to build in quality (this sounds awkward)  Collect more information  Implementation of the 5S methodology By implementing these changes, the future state map was created and the total lead time was reduced from 8 days to 6 days. The production lead time reduced from 4.35 days to 4 days
  5. 5. 5 Introduction The main focus of companies in the 20th century was the customers. It has become more and more competitive to satisfy customers (Gaither 1994). For instance, to perform in a global market, short lead times are essential to provide customer satisfaction. Organizations that have focused on cycle time as a productivity measure can reduce delivery time and improve quality, thereby creating more satisfied customer. Cycle time or lead time is from the time a customer release an order until the time they receive the finished product. (Gaither 1994) Before 1980, customers tolerated long lead times which enabled producers to minimize product cost by using economical batch sizes. Later, when customers began to demand shorter lead times, they were able to get them from competitors. This is when the problem arose and companies started to look for changes to be more competitive. In an attempt to reduce lead time, businesses and organizations found that in reality 90% of the existing activities are non-essential and could be eliminated. As soon as manufacturers focused on processes, they found waste associated with changeovers, quality defects, process control, factory layout, and machine down time. So they tried to find ways to reduce or eliminate waste. By eliminating the non-value adding activities from the processes and streamlining the information flow significant optimization results can be realized Many trends affect the metalworking industry, including customer demands for the best quality, lowest cost and shortest delivery time. Design concepts for modular machine tools can address these expectations through general-function modules that can be combined to meet job requirements while reducing costs and lead times. Modular machines benefit large production facilities with their ability to easily interlink and form work cells, while smaller facilities profit from their flexibility, with all users enjoying lower investment costs compared to custom, turnkey solutions. Available for chucked components and shaft work pieces, modular machines can increase production with their shared, basic designs. The work area of a cutting tool modular machine tool The goal behind cutting tool modular concept was to develop a platform that enables engineers to form manufacturing cells easily while enhancing precision and productivity. Most importantly, modular machines offer more flexibility with the integration of a range of manufacturing technologies for an extensive product lineup, allowing quick and efficient changeover to meet evolving production requirements. This flexibility enables manufacturers to change the way they use modular machines over time. The most obvious advantage is capitalizing on a shared operating and parts strategy. Regardless of the technology, these machines use identical components, from human/machine interfaces to drive controllers and motors, for their basic design. Not only does this allow end users to simplify operation, but also procurement because they
  6. 6. 6 reduce their spare-part inventories. This component-commonality strategy can increase profitability by reducing spare-part investment and warehousing costs. Operators and mechanics benefit from the streamlined design as well. A modular machine speeds changeovers and maintenance to increase throughput. Because the base modules remain consistent, a modular design shortens the learning curve for new employees, as well as experienced workers when new machines are put into production. Additionally, modular designs save floor space. Each machine has a compact design to minimize its footprint. This also allows them to be positioned close together. For loading and unloading work pieces, cutting tool modular models feature integrated, automated pickup bands, or conveyor belts, at a uniform transfer height, simplifying the integration of robots and transfer units, if required. Machine tool builders also see advantages to providing modular concepts. Not only do they benefit from the smaller component inventories that come with a common parts strategy, but a modular approach means less development time while still having the ability to integrate machine functions. Systems are broken down into small units, with the awareness that these units will be common to different applications, yet brought together as needed for the final design. All products must evolve, and a modular design shortens the development and redesign cycle to that end. This is because a machine tool builder can reuse most of the old modules for its latest-generation machine and change only the ones that need improvement. As the market continues to demand increased performance despite decreasing budgets and an emphasis on a quick return on investment, the attractive price-performance ratio of modular machines will increase their market penetration. This shows that a simple concept can deliver the best solution.
  7. 7. 7 Background Cutting Tool Technology  Tool Life  Tool Materials  Tool Geometry  Cutting Fluids Three Modes of Tool Failure  Fracture failure ◦ Cutting force becomes excessive and/or dynamic, leading to brittle fracture  Temperature failure ◦ Cutting temperature is too high for the tool material  Gradual wear ◦ Gradual wearing of the cutting tool Preferred Mode of Tool Failure: Gradual Wear  Fracture and temperature failures are premature failures  Gradual wear is preferred because it leads to the longest possible use of the tool  Gradual wear occurs at two locations on a tool: ◦ Crater wear – occurs on top rake face ◦ Flank wear – occurs on flank (side of tool) Tool Life Criteria in Production 1. Complete failure of cutting edge 2. Visual inspection of flank wear (or crater wear) by the machine operator 3. Fingernail test across cutting edge 4. Changes in sound emitted from operation 5. Chips become ribbony, stringy, and difficult to dispose of 6. Degradation of surface finish 7. Increased power 8. Workpiece count 9. Cumulative cutting time Tool Materials  Tool failure modes identify the important properties that a tool material should possess: ◦ Toughness - to avoid fracture failure ◦ Hot hardness - ability to retain hardness at high temperatures ◦ Wear resistance - hardness is the most important property to resist abrasive wear Twist Drill Operation
  8. 8. 8  Rotation and feeding of drill bit result in relative motion between cutting edges and workpiece to form the chips ◦ Cutting speed varies along cutting edges as a function of distance from axis of rotation ◦ Relative velocity at drill point is zero, so no cutting takes place ◦ A large thrust force is required to drive the drill forward into hole Twist Drill Operation – Problems  Chip removal ◦ Flutes must provide sufficient clearance to allow chips to be extracted from bottom of hole  Friction makes matters worse ◦ Rubbing between outside diameter of drill bit and newly formed hole ◦ Delivery of cutting fluid to drill point to reduce friction and heat is difficult because chips are flowing in the opposite direction In this section of the thesis, the problem definition and introduction to perfect profile centre is presented. In today’s competitive business world, companies should have small lead times, low costs and high customer service levels to survive. Recently low cost countries have huge share in market and they are growing to great extent. To achieve high service levels, companies should make the flow of information, material and resources as efficient as possible. Therefore it is important to know how a company performs its business and communicates with its suppliers and customers. Having a good relationship with ones supplier and customer is a key success factor in today’s business world. This study was based on the work accomplished for perfect profile centre. The main products of this company are labels and etiquettes. At perfect profile centre, the lead time for each repeated order was approximately 8 days, and for new orders the lead time was 10 days. Perfect profile centre’s goals were to reduce this lead time to less than a week with a corresponding reduction in cost thereby improving of performance of company. Value stream mapping was selected because it was a good methodology to visualize a company’s performance. By creating current state map, value adding and non- value adding activities were determined. Areas of improvement could be distinguished and proper actions for waste elimination could be taken. To achieve a future state map, different lean principles could be implemented.
  9. 9. 9 Scope of the study: The project is based on the secondary data available at the company and the primary data collected at the company by observing delayed deliveries.  The study of delayed deliveries at Perfect Profile Centre.  The study was limited to CNC machines only.  This study will help the company to get solution to control late delivery of the orders. Objectives of study:  To study the process of manufacturing cutting tools.  To study gap between expected delivery time and actual delivery time.  To find out reasons behind late delivery of orders. Profile ofOrganizational Company: Perfect profile centre is a small scale industry, a proprietary firm established in 1995 and is manufacturer of solid carbide cutting tools and profile form cutters. Company supplies cutting tools to various automobile companies as well as to other small scale industries. Products: The manufacturer of standard as well as special purpose cutting tools as per the customer demand for milling, turning, drilling, boring etc applications.  Drills  Reamers  End mills  Ball nose cutters  Brazed cutters  Profile cutters The design, manufacture and supply of custom cutting tools tailored to specific customer requirements. Major Customers:  Tata Motors
  10. 10. 1  Mahindra Motors  Cummins India PVT LTD  Hindustan Pencils  Sandvik Asia Equipments: Perfect Profile Centre has setup of conventional as well as CNC machines with help of which manufacturing of cutting tools are done. In conventional machines manually operated machines are available such as tool and cutter, Optical Profile Grinding, milling, cylindrical grinding machines. For brazed cutters brazing unit is available with the help of which, carbide tip is fixed on the steel shank of the tool. In CNC three 5-axis CNC machines are available out of which two machines are used for roughing purpose and one is used for finishing. With the help of CNC machines, cutting tools can be manufactured within tolerance which is acceptable to the customer. Process: For different tools different steps are followed: 1) Drill/End mill/Reamer/Ball nose Cutters: i. Cutting the rod of required length. ii. Brazing false centre iii. Cylindrical grinding to obtain required diameter iv. Parting(To remove fall Center) v. Facing(To clean unclean face after parting) vi. Fluting vii. OD reliving viii. Point angle 2) Brazed Cutters: i. Cutting the rod of required length ii. Turning iii. Milling iv. Hardening v. Tip Brazing vi. Tip Grinding
  11. 11. 1 Theoretical frame of reference There were several different approaches when discussing lead time reduction. The one approach that was selected for this master thesis was implementing lean principles to eliminate wastes. Therefore it is important to understand the lean philosophy, lean principles, the definition of waste, and different kinds of waste. To properly and thoroughly discover those areas with waste, all processes must first be mapped. There also were many different types of process mappings with each possessing its own level of suitability for particular situation. The following theoretical frame of reference is comprised of theories on both lean manufacturing and process mapping. In the next section the history of lean manufacturing a r e discussed. After an introduction to lean manufacturing, different types of process mapping are discussed along with their strengths and weaknesses. In the beginning of 1980, the western automotive industry began to realize that the Japanese way of manufacturing vehicles far exceeded the methods that were used in the European and American industries. Japanese companies achieved higher productivity and better quality using less resource. A major research project was therefore initiated at the end of 1980 by Womack, Jones and Roos, at the Massachusetts Institute of Technology. The research showed a significant gap in productivity and quality between the Japanese vehicle assembler and the rest of the vehicle assemblers in the world. The term “lean production” was then developed to describe the Japanese production philosophy. Lean production was not confined to the activities that took place in the manufacturing function of a company, rather it related to activities ranging from product development, procurement and manufacturing to distribution. Together these areas defined the lean enterprise. The ultimate goal of implementing lean production in an organization was to have the customer in focus when improving productivity, enhancing quality, shortening lead times, reducing costs, etc. Product delivery strategies There are four major product delivery strategies for a manufacturing company; engineer-to-order, make-to-order, assemble-to-order and make-to-stock The four mentioned product delivery strategies have different performance levels regarding fulfilling these demands and the required amounts of tied-up capital in the processes. The point in time where the customer order is used for customize a product is called the customer ordering point. Before this point the material structure; the Bill of
  12. 12. 1 material, is generally purchased and refined based on forecast. After the customer ordering point all value adding work is customer driven. Engineer-to-order: to develop and manufacture a new customized product generally requires very long lead times for companies. If a customer accepts long order-to- delivery lead times and demands a very specialized product for fulfilling his needs; engineer-to-order is the right delivery strategy. Engineer-to-order has the earliest customer ordering point and requires the least amounts of tied-up capital of the four strategies since no raw material has either been purchased or refined before receiving a customer order. Make-to-order: if a customer demands a specialized product but doesn’t accept the company’s lead time needed for product development; the company has to develop several products ready for manufacturing when receiving a customer order. This strategy gives shorter lead times than engineer-to-order due to a later customer ordering point. This provides less product flexibility and requires higher amounts of tied- up capital, since raw material must be available for manufacturing when receiving a customer order. Assemble-to-order: in order to further decrease order-to-delivery lead times, but still offering nearly as large product flexibility, a modular system can be created. Then basic components, that are same for all product variety, are manufactured in advance based on forecast and can be assembled in different combinations giving product flexibility. The trade-off with this strategy is the amount of tied-up capital that is higher when having manufactured components available in stock for final assembly at the customer ordering point. Make-to-stock: If the customers’ order-to-delivery lead time demand is shorter than the manufacturing company’s final assembly and delivery lead times together; make-to- stock is the only effective product delivery strategy. The finished goods products are manufactured based on forecast, which limits the product flexibility, when just having a predetermined types and volumes of products available in stock for customer orders. The delivery lead time for make-to-stock is the shortest of the four strategies but the amount of tied-up capital is the highest. The more value adding work that is put on a product to process it in advance; the shorter lead time to customer, but the higher amounts of tied-up capital and the lower product flexibility is achieved. Based on these four strategies; several combinations of mixed strategies can be created for a product flow. For example when having both high and low runners; make-to-stock is often used for the predictable high runners in order to even out the production workload and thereby save capacity for the unpredictable customer demand for low runners through make-to-order.
  13. 13. 1 Lead time reductions theories According to Kuhlang, lead time is defined as “that period of time (hours, minutes etc.) required by any process to transform the inputs (materials, customers, money, information) into outputs (goods, services).” The lead times for production are affected by factors like capacity, loading, batching and scheduling. In turn, the lead times affect factors like cost and control. A product flow with shorter lead times has a higher output and increases the value added to the product within a certain time. Alternatively, the same value can be added to the product in shorter time. The aim for the processes is to perform the value added work within the shortest possible time. Sources for reducing the lead times in a product flow are for example process times, transportation time and idle time. Long lead times entails increasing the costs due to larger buffers, increased uncertainty about requirements, larger safety stocks and broken delivery promises), whereas short lead times are beneficial for both the supplier and the customer. In several literature sources on operations management, it is stated that customer demand increases with lower delivery times as well as with lower prices. Consequently, lead times are inversely related to market shares. Reducing the manufacturing lead times allows for the company to react faster to customer demand and by that postpone the production start. A lower share of the products thereby needs to be produced towards forecasts and the risks for stock out or over production are reduced. The lead times, along with the price, have a large impact on the supplier’s possibilities to secure customer orders. The extent to which the supplier is able to deliver the goods within the lead times quoted, may be decisive for where the customers place their orders. Reliable lead times are utterly important for the customers, allowing them to forecast their demand and make plans they can depend upon. These preconditions are difficult to live up to with make to order production. The planning and control of the make to order production are often complicated due to high variations in product range and process times. The complexity is further increased by unforeseen factors affecting the production like breakdowns, employee sick leave and delayed supply of raw material. Additionally, the customers place orders irregularly, causing an uneven demand on the production capacity. The consequence of these factors is that the lead times for make to order production often are long and unreliable. Strategy of Lead Time Reduction There are different approaches and strategies regarding lead time. In the production management, theoretical evidence describes and gives importance on. Look for WIP. The more WIP the longer will the lead time be. Keep Things moving: if the product moves in a continuous flow against finished product both WIP and flow time will decrease.
  14. 14. 1 Synchronize production: Whit synchronized production the WIP will reduce and due to this the lead time will decrease. Smooth the work flow: An even work load affect the lead time whit an increase in both variance and long flow times. Eliminate variability: Variability can be caused of a number of causes e.g.: lack of consistency, downtime and rework. The typical approaches had taken in the last century to focus on the manufacturing processes. The researcher in past also gave their endeavor to improve the value added processes regarding lead time reduction. After the successful implementation of lean philosophy especially in Toyota, intention has been growing on reducing the non value added activities time. Moreover the overall impact of reducing processing time has very little influence over the lead time will be minimal. Many industries and found 90-95 percentage of none value added activities in lead time. Elimination of waste Lean production was about creating value for the customers with a minimum amount of waste and with a maximum degree of quality. Waste was defined as any activity that consumes resources and creates no value, i.e. lean thinking. Identification and elimination of waste makes it easier to focus on value adding activities and to become more cost efficient. The sources of waste included: 1. Overproduction 2. Defects 3. Unnecessary inventory 4. Unnecessary processing 5. Unnecessary transportation between work sites 6. Waiting 7. Unnecessary motion in the workplace These seven sources of waste will now be explained in detail together with tools to detect and reduce them.
  15. 15. 1 Overproduction waste The most significant source of waste is over production. This means producing more, sooner or faster than what is required by the next process. Overproduction causes all kinds of waste, not just excess inventory and money tied up in inventory. It results in shortage, because processes are busy masking the wrong items. Traditionally supervisors were judged by the quantity of production. The thought was that resource utilization was to be maximized. This led to overproduction waste. According to lean philosophy Machines and humans should only be busy when they have useful tasks to accomplish. Lean production accentuates on production according to customers’ demand, otherwise products would have to be stored and the risk of becoming obsolete increases. Overproduction is more common when products are made according to forecasts instead of customer’s order. Therefore it is reasonable to produce according to customer’s orders. Since customers demand for delivery is often shorter than the production lead time, forecasting is inevitable in most cases. As a result, the customer order point should be moved upstream in the production flow.
  16. 16. 1 Defect waste The lack of quality is another source of waste. When a product or a part is found to be defective, it should be rebuilt. This means the consumption of more resources, higher costs also provides for a negative impact on the customers perception. It is important to find the root of the quality problem and remove the problem from its source. The bigger the batch size, the more time it will take to detect a defect. This can cause the entire batch to be scraped. In one piece flows, defects are detected immediately and the operator causing it can get instant feedback from their downstream customer. Unnecessary inventory Keeping parts and products in inventory does not create any extra value for them. When this occurs, it only hides the problem and prevents a solution. Additionally, keeping inventory means higher tied up capital. However, it is not advisable to eliminate inventory mindlessly. Instead, the reason for the existence of the inventory must first be found (Karlsson and Åhlström, 1996). Two types of inventories are existed: work in process (WIP) and parts storage. WIP are the parts stored between each process and parts storage are the raw material which were brought from the main ware house to the production area to be processed. Lean manufacturing always emphasizes on reducing inventory. This can be done either by reduction of buffer inventory or the reduction of batch sizes, or both. Buffer inventory is reduced by eliminating unwanted variations. The positive points for reducing inventory are listed below:  Reducing tied up capital  Shortening through-put time  Lessening risk of obsolete material  Smoothing production flow  Lowering space rental costs  Decreasing the time needed to detect quality problems
  17. 17. 1 The list above indicates that reducing inventory is related to other sources of wastes such as the waste of time, defective products and unnecessary transportation. It also indicates that reducing inventory helps in reducing other areas of wastes. Unnecessary processing An Incorrectly designed process could also be a source of waste. Activities in an organizational process can be divided into 3 categories: value adding, non-value adding but necessary, and non-value adding and unnecessary. Lean production emphasizes reducing this non-value adding and unnecessary process. Changing design of parts, limiting functionally unnecessary tolerances and rethinking process plans can often eliminate and simplify process activities in the manufacturing process (Askin & Goldberg 2002). A tool for determining non-value adding activities is process mapping. All steps in a process are indicated by graphical symbols with different activities linked by arrows. A detailed map of a process often reveals unnecessary stages and sequences, and can be used to improve the process design (Brassard & Ritter 1994). Unnecessary transportation between work sites Transportation waste includes all types of unnecessary transportation of material, work in process and components, which do not add value to the products. Most unnecessary transportation is due to the inappropriate layout of a factory. As such, it is difficult finding methods to optimize the layout of a factory. One method to address this is the traditional view in accordance with the mass production perspective. This means that machine and equipment are often grouped on a functional basis. This layout maximizes transportation efficiency between functional areas. This is in keeping with a lean manufacturing layout that is based on product families and dedicates equipment to each product family. This is necessary to achieve a flow with minimal transportation. One tool that can be used for analyzing transportation waste is spaghetti mapping. A spaghetti map indicates physical flow of material, products and humans. Basically, all movements are drawn on a current layout map in order to reveal unnecessary transportation. The map often looks like a pile of spaghetti before the layout is improved. This is the reason it is called spaghetti mapping.
  18. 18. 1 Waiting Waiting may be due to different reasons such as waiting for correct information, products waiting to be processed, machines waiting for their operators and machines waiting for material to arrive. One such common type of waste is waiting associated within inventories. Research has showed that products spend most of their time in warehouses. Value Stream Mapping is a tool for identifying the product flow through the factory. Processing time, throughput times, set-up times, inventory levels, etc., are mapped with standardized symbols. The map reveals the relationship between waiting and processing times. It is not uncommon to find that the value adding time is only a few percent of the total lead time. Unnecessary motion in the work place Motion consumes time and energy. It is essential to eliminate all motion that does not add value, such as stretching for tools and moving materials within a station. This objective should be guiding when designing workplaces, processes, operation procedures, etc. Reducing waste as the result of unnecessary motion encompasses everything from describing detailed hand motions in an assembly process to the selection of machines and design of fixtures to reduce the time for set-ups and material handling. Solid carbide cutting tool Production System Each part of the house is important, by itself, but when they work together, they reinforce each other. One piece flow means that one unit at a time is processed at the customers demand rate, which will enhance judoka. In mass production when a machine goes down, the maintenance department will fix the problem. Inventory is then
  19. 19. 1 used to fill the production gap during these times. Thus, there will not be any urgency. Whereas in lean production when a machine goes down other operations will soon stop production, so there is always some urgency to fix the problem. Theoretical frame work on process mapping It is important to understand the definition and importance of a process. Ron Anjard (1998) defined a process as “a series of activities (tasks, steps, events, operations) that takes an input adds value to it and produces an output (products, service, or information) for a customer. Customers are all those who receive the process output.” In order to understand, document, analyze, develop and improve process steps, a process map is vital. A process map is a visual aid for depicting the work process. It shows how inputs, outputs and tasks are linked. (Anjard 1998) A process map can be drawn at various levels of detail. Some have described it as “peeling the onion.” All process maps should be developed from a top-down approach. One should begin mapping at the macro level of the process. This level determines the scope of the system. Then the process should be “peeled” down to the mini-level of the process. A single process may break down into 5-15 mini-processes. (Anjard 1998) According to Aguiar and Waston (1993), process mapping can improve the customer focus of the process, assist in eliminating the non-value added activities and reduce the process complexity. Process mapping is usually consisted of the following steps: 1. Identification of products and services and their related processes. The starting and finishing points of processes are identified at this step. 2. Data gathering and preparation. How to conduct process mapping Different steps in process mapping were introduced by Savory and Olson (2001) as follows: 1. Defining the purpose for developing a process map 2. Establishing the team 3. Mapping the “As Is” process
  20. 20. 2 4. Establishing a measure for improvement 5. Proposing changes 6. Mapping the “Should Be” process Step1: Defining the purpose for developing a process map It is extremely important to know the goal and aim for creating the process map. It identifies the depth and the level of process mapping. Step 2: Establishing the team The team should consist of representatives from different levels of the organization. Some key suppliers and customers can also be engaged with mapping. Step 3: Mapping the “As Is” process In this step the process is mapped exactly the same way as it occurs at the present time. This is done by interviewing key personnel involved in that particular process. It is necessary to understand that this map is never 100 percent correct by first trail, but it will provide some idea about opportunities for improvement in the future. Step4: Establishing a measure for improvement Having the “As Is” map without any performance measurement is useless. Since the goal is to improve the process, there should be some way to measure the improvement. A direct link has to be established between the target for improvement effort, the organization’s strategy and competitive position. Step5: Proposing changes After preparing an “As Is” map and establishing an improvement measure, the improvement areas should be determined. Some of these improvement areas are described by Savory and Olson (2001):  Eliminate duplicate activities  Combine related activities  Eliminate multiple reviews and approvals  Eliminate inspections  Simplify processes
  21. 21. 2  Perform activities in parallel  Outsource inefficient processes  Recognize worker teams Step6: Mapping the “Should Be” process The “Should Be” process map presents the ideal situation. It describes the process after all non-value added processes are eliminated. It shows a new or improved process that meets the goals established and eliminates deficiencies. Different mapping tools In this chapter different mapping tools and their descriptions are presented. Among existing mapping tools, flowcharts, Supply-chain Operation Reference- model (SCOR), Value Stream Mapping (VSM), and Time Based Process Mapping (TBPM) are taken into consideration. Value Stream Mapping (VSM) VSM is a tool to understand the material and information flow as a product or service makes its way through the value stream. VSM takes into account not only the activity of producing the product, but also the management and information systems that support the basic process. This is especially helpful when working to reduce cycle time and to gain insight into the decision making flow, as well as the process flow. This is actually a Lean. The basic idea is to first map the process. Then above that, map the information flow that enables the process to occur. The value stream map takes into account different measures such as cycle time, set up time, lead time, and value added time, size of batch, number of operators, number of products, shipment volume, labor hours, rework of products and cassations. Different steps exist within VSM. First, the current state map is created to show the current production situation. Business and manufacturing waste that occurs in this process can be easily identified. Once the current state map has been created, it then becomes the baseline for improvement and for the creation of a future state value stream map. After all, VSM is only a tool unless the future state is achieved.
  22. 22. 2 The purpose of VSM is to identify, demonstrate and remove waste in processes. Waste is defined as any activity that creates no value for the customer. VSM can be a starting point to help management engineers, production associates and suppliers to recognize waste and identify its causes. As a result, VSM is a tool for communication, but it can also be used as a strategic planning tool and as a change management tool. In this regard, mapping out the activities in the manufacturing process with cycle times, down times, in- process inventory, material moves, information flows, helps to visualize the current state of the process activities and helps the development of the future desired state. Literature Review There has always been some level of competition within the realm of manufacturing. Technological advances in communication and transportation have made this competition a global one that continues to put increasingly greater pressure on businesses to produce products (or deliver services,) of better quality and with faster lead times, all while providing the best customer service. A number of tools and techniques exist to help these businesses in this endeavor. Among the tools being utilized by companies today are the principles of lean manufacturing and simulation software. The purpose of this project is to simulate the entire production system for an injection molded and chrome plated, automotive component to determine if the amount of work in progress and finished goods inventory can be minimized in order to reduce the cost of inventory in the overall system. Simulation The world of manufacturing is full of situations in which change is desirable for one reason or another, but the cost to trial the change is not justifiable. Simulation can be a very useful tool in this scenario, allowing an observer to measure and predict how changes to the individual components of system will affect the functionality of the overall system. A simulation is a type of computer program that uses a mathematical description of the real system called a model. This model is created for the sole purpose of conducting numerical experiments to aid in the understanding of the behavior of the system being modeled, for a specific set of conditions. Computer simulation is often chosen for its ability to handle very complex systems and analysis. Yet the actual use of simulation is a very natural activity, comparable to that of role playing. The reality and complexity of a scenario can be understood by acting out roles with artificial objects (models.) The electronic equivalent to this role playing is computer simulation. Simulation Uses / Applications Computer simulation is often chosen for use when one or more of the following situations is true: the model is quite complex with multiple variables and interacting components, there are nonlinear relationships between the underlying variables, random variants exist in the model, and / or there is a desire to show what is happening in the model using a 3D computer animation.
  23. 23. 2 Simulation has already been or could be used for such a vast array of applications it is somewhat difficult to classify all of them. A broad, representative list of categories would include computer systems, manufacturing, business, government, ecology and environment, society and behavior, and biosciences. Each of these categories in tom could have a wide variety of applications within it that simulation is useful for. In reality, it would be difficult to find an application that simulation could not be used for. In cases where simulation is not desirable for a given application it is generally due to the cost and timing of both acquiring software and training to use it, as well as for conducting and analyzing the results, not because it did not fit the application. Simulation Models "A model is a simplified representation of a system at some particular point in time or space intended to promote understanding of the real system." (Bellinger, 2004). It is not possible to create a model that perfectly depicts every aspect of reality, though we can get close enough to learn from it. . There are specific steps that should be followed when conducting a simulation in order to ensure that the outcome achieved correlates with the type of problem that the experimenter desired to solve. Methodology The aim of this project is to reduce lead time by implementing lean principles; therefore the output of this project should be applicable in improving the current situation. To be able to accomplish this, first theories were studied, and then those theories were implemented into a case study using perfect profile centre, in Pune. Data were collected from different sources and in different ways. Most information was gathered by interviewing different employees. At the beginning, some brief information was collected from the production manager concerning different departments and their activities. Next, the staff of each department was interviewed which provided general knowledge about each section’s roles. To create the VSM some orders were followed directly from the order point to shipping. This was done by interviewing operators, walking the shop floor and collecting information, to include the gathering of information from computers. In the beginning, maps were drawn with pencil on paper and later transcribed to electronic format. Times for each process step were measured using a stopwatch and calculations were performed when necessary. The theoretical framework consisted of two different parts: 1. Lean principles and cutting tool production system 2. Different methods of process mapping
  24. 24. 2 After putting theories into practice, for the perfect profile centre case study, some results were driven and analyzed. Recommendations concerning different ways to reduce lead times and various production improvements were derived from the future state map, and were presented to the company. To create the VSM for perfect profile centre, a map was created according the instructions in the book, Learning to See. Almost all of the different steps were covered. Some assumptions were made during creation of the first map. This was mainly done for the sake of simplicity. One such case concerned the fact that there were not enough statistics and information on waiting times, idle times and other timings. Different orders were followed from the ordering point to the production point and afterwards to the shipping point. No trend was found between different time divisions. Therefore one of the orders was randomly selected and used for creating the necessary maps. To acquire some knowledge about change-over actions, different change-over steps were observed three times. The operators were interviewed about different methods to reduce changeover time. Some data collection was made from interview, observation, literature studies and by following orders. The next chapter discusses the VSM created for perfect profile centre and the different steps within it. Different waste areas were identified and some solutions were recommended to reduce lead times, which resulted in the creation of a future state map. The future state map shows the process as it should be in the future after implementing some specific changes. The most important step, though, is to make the future state map work in practice and see the corresponding results. Evaluation of methods and data The methods used for data collection and information gathering were mainly based on interviews. The accuracy of these interviews depended mainly on the precision and depth of the interviewee and interviewer. In this case most of the data were also saved in an electronic format which has ensured the accuracy and security of the data. One difficulty with gathering information at perfect profile centre was that order data were not retained for future analysis. In most cases the order information that was saved consisted of: ordering date, work duration, change-over duration and delivery date. Waiting time, idle time and other pertinent order information were not kept. Also, there were no statistics concerning different orders. All conclusions made in this thesis are based on several orders that were tracked and traced.
  25. 25. 2 The methods used in this study were mainly process mapping and VSM. These methods were accurate methods used by many other researches. They are basically strong methods but still the accuracy depends on the precision of the collected data and the capabilities of the person collecting the data. The recommendation and conclusion portion of this thesis is primarily based on the related principles found in the cutting tool. These principles have been used by cutting tool for years with brilliant results. There has been a tendency for small and medium size companies to use these principles, and good results were achieved in small and medium size companies. The reason for this is due to the principles being sufficiently general and thus applicable to different situations. A description of each department and its role is presented in the following sections. Production Department Each order was produced by an assigned press machine. Depending on the customer’s request, orders may have gone through a converter to reduce the rolls’ diameter or orders have been fan folded by special machines. The waiting time before pressing varies between one and six days, depending on the number and type of orders of previous orders. This was one of the limitations in mapping the process. There was no information or rules concerning wait times before pressing. Sometimes wait times can become so long that the material planner decides to move the order to another press machine, which had less work load at that time. Each machine had one operator who controls every step. That assigned operator should not leave the machine when it is running. The work day consisted of one shift lasting for Since only two converters existed, it may take from one hour to two days for rolls of labels to be converted. The waiting time before the converter varies significantly, also. Sometimes it takes a few minutes and sometimes rolls have to wait for one day to be converted. The final labels may have remained in the warehouse for a few days or shipped immediately after production. Orders in which the supplier had assigned a specific delivery date may have stayed in the warehouse until the desired delivery date. Others were shipped sooner, if they were ready.
  26. 26. 2 Identification of the problem This is where one must decide what the true problem is that needs solving or at very least what the symptoms of the problem look like... A very important part of this problem identification step is to clearly define what the goals of the study are so that everyone involved knows exactly what question is to be answered. Development of the actual simulation model begins when the definition of the system is complete. . This order has to be followed because the system definition is now used as the framework for completing the model build. Proposed Methodologies This chapter describes how the project was conducted, and on what theoretical framework it is based. The research strategy is worked out to provide for a methodical approach to the research and to point out its direction. The different stages for performing the study are described and motivated. In this chapter three methodologies are presented to minimize the cycle time at Perfect profile centre environment. The chapter is divided into three sections: In the first section the development of a heuristic algorithm based on a new dispatching rule is presented. This section details on the development of an algorithm, which is subsequently analyzed using simulation software. The second section details the development of a mathematical based program to model the wafer fabrication system. An integer programming model is developed and analyzed. Various modifications are suggested for improved performance. The third and last section presents an approach to minimize the maximum cycle time using a conjunctive disjunctive graph based approach. Batching Machines Some machines are capable of processing more than one lot at a time. These machines are referred to as batching machines. The batching machines have a specified minimum batch size, as well as, a specified maximum batch size, which they can process at one time. Each time a batching machine selects lots from its queue to be batched, it checks if the minimum batch size has been attained. If the minimum batch size has not been attained, then it will wait for more lots to enter its queue.
  27. 27. 2 Machine Downtimes The machines are subject to failures and calibrations. Both these events are defined as downtime for a machine. Research Methodology Research is defined as a systematic, gathering, recording, and analysis of data about problem relating to any particular field. It determines strength reliability and accuracy of the project. The research involved both qualitative as well as quantitative dimensions of work. The quantitative approach involved collection of large chunks of data. The quality approach was to analyze the data, take the necessary information and to find out conclusion. Selection of research topic based on:  Magnitude of the problem and its impact.  Urgency of the need for a solution.  Feasibility of the approach.  Chances of success. Research design: Research design pertains to the great research approach or strategy adopted for a particular project. A research project has to be the conducted scientifically making sure that the data is collected adequately and economically. Types of research design 1. Exploratory research design: This research design is offered when researcher has a vague idea about the problem the researcher has to explore the subject. 2. Experimental research design: It is used to provide a strong basic for the existence of causal relationship between two or more variable. 3. Descriptive research design: It seeks to determine the answers to who, what, where and how questions. It is based on some previous understanding of matter. 4. Diagnostic research design: It determines the frequency with which something occurs or its association with something else.
  28. 28. 2 Research design used in this project: Source of data collection: Primary data: The data necessary for the study has been gathered from following sources.  Day to day interaction with operator  Day to day interaction with manager  Day to day study of list of work orders. Secondary data: Secondary data means data which is already available with the organization. The researcher has to look into sources for data from where he can obtain data. The secondary data may either be published or unpublished.  Standard data of time study.  Delivery registers of the company.
  29. 29. 2 Method of analysis: Manufacturing process: For Drill/End mill/Reamer/Ball nose Cutters: Rod cuttingto required length Making 140̊ angle at both faces Cylindrical grinding Facing Fluting OD reliving Point angle
  30. 30. 3 For Brazed Cutters: Cutting the rod to required length Turning Milling Hardening Tip brazing OD grinding Tip grinding
  31. 31. 3 Drills, End mills, Reamers, Ball nose cutters are manufactured from solid carbide rods and brazed cutters are manufactured from EN24 material and then carbide tips are brazed on the cutter body with the help of brazing flux and flame of mixture of oxygen and acetylene gas. After completion of the process, tools which are manufactured from solid carbide are sent for coating process, and oil is applied to brazed cutters in order to prevent it from corrosion. Current state analysis The lead times for the current state of the production flows were compared to the lead times required by the customers. The comparison showed if the required lead times would be possible to meet with the make to order production of the different products. The future state proposals are not developed to meet the customer needs requiring lead times which not can be met with make to order production.
  32. 32. 3 Data collection,Analysis and interpretation Expected and actual processing time: TimeWasted Order NumberTotal TimeCycle time Setting Time Total time Cycle time setting time by Operator(Min) 1 30 15 15 60 19 25 16 2 45 30 15 50 32 15 3 3 20 15 5 30 18 10 2 4 120 90 30 180 105 45 30 5 75 30 45 75 25 45 -5 6 60 25 35 60 25 55 0 7 20 10 10 25 10 10 5 8 30 15 15 65 20 25 20 9 180 150 30 270 180 45 45 10 120 90 30 150 100 35 15 11 20 15 5 35 18 10 7 12 60 25 35 60 25 35 0 13 45 30 15 55 32 15 7 14 60 25 35 75 25 35 15 15 40 25 15 45 25 20 0 16 90 70 20 105 75 20 10 17 15 5 10 20 5 15 0 18 35 20 15 40 22 15 3 19 60 25 35 60 25 35 0 20 20 15 5 20 15 5 0 21 60 25 35 60 23 35 -2 22 135 105 30 150 105 35 10 23 180 150 30 255 165 45 45 24 15 10 5 15 10 5 0 25 20 15 5 20 15 5 0 Expected(Min) Actual(Min)
  33. 33. 3 Time wasted Order Number Total Time Cycle timeSetting TimeTotal timeCycle time setting time by Operato(Min) 26 75 30 45 75 30 40 -5 27 60 40 20 75 40 25 10 28 35 25 10 40 25 15 0 29 30 15 15 45 15 20 10 30 135 110 25 150 110 30 10 31 60 45 15 75 45 20 10 32 20 10 10 20 10 10 0 33 45 30 15 50 32 15 3 34 20 15 5 20 12 5 -3 35 60 25 35 60 25 30 -5 36 35 25 10 40 25 15 0 37 20 10 10 25 10 15 0 38 75 30 45 90 30 45 15 39 20 15 15 30 18 10 2 40 120 90 30 3 105 45 30 41 30 15 15 45 15 15 15 42 40 25 15 45 25 15 5 43 240 210 30 310 225 30 50 44 35 25 10 40 25 10 5 45 60 45 15 75 45 20 10 46 20 15 5 25 17 5 3 47 180 150 30 255 155 45 55 48 20 10 10 20 10 10 0 49 60 25 35 60 30 30 0 50 20 15 5 20 13 7 0 Total 3070 2080 1000 3673 2211 1167 446 Expected(Min) Actual(Min) 0 500 1000 1500 2000 2500 3000 3500 4000 4500 Total Time Cycle Time Setting Time Expected Actual
  34. 34. 3 For delayed orders: Order no Expected processing Time (Days) Actual processing Time (Days) Delay 1 2 4 2 2 1 3 2 3 2 3 1 4 1 3 2 5 2 4 4 6 5 6 1 7 3 5 2 8 2 4 2 9 1 6 5 10 1 5 4 11 1 2 1 12 1 3 2 13 1 3 2 14 1 3 2 15 1 4 3 16 1 6 5 17 1 4 3 18 1 5 4 19 2 3 1 20 2 3 1 21 1 3 2 22 1 3 2 23 1 3 2 24 1 3 2 25 1 2 1 26 1 3 2 27 1 3 2 28 1 2 1 29 2 5 3 30 2 4 2 31 2 3 1 32 2 3 1 33 2 4 2 34 2 5 3 35 2 4 2
  35. 35. 3 Findings & Suggestions This chapter will provide the recommendations concerning waiting time and finally about reducing the lead times. However, the project work will only provide the plan of continuous improvement but it might be better to experiment the new recommendation and compare it with previous state of production. One important fact has considered before given new proposal. Perfect profile centre has requested to give new proposal within their existing resources. The Company did not want to invest capital, machineries, any major change in their current system etc right now. Hence, the solutions offer according to those considerations. Each priority of root cause will given the description of problem and pursues the probable best solution for improvement of lead-time. Transfer Batch or lot size Policy The production method in Perfect profile centre has been running based on batch production. The production control unit release customer order as batch in production floor. The batch size are varies according to customer order. The increased batch size eventually increases the waiting time. The characteristics of Perfect profile centre have like job production where a significant flexibility is present due to customization and model varieties. In addition, sewing unit has no identical layout. There is no cell or balanced line or group workstation. The employee work individually when they start an order to sew 2 1 2 1 1 2 2 5 3 2 1 3 1 1 1 1 1 1 2 2 2 1 1 3 3 3 1 2 2 1 1 2 1 4 3 3 3 1 2 4 11 13 8 6 3 5 2 3 3 3 4 2 2 2 6 4 3 3 3 5 3 3 3 3 2 3 0 2 4 6 8 10 12 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Expecte d Time Actual Time
  36. 36. 3 upholstery. The model of upholstery varies consequently the amount of process varies. The employee then makes all processing by walking and moving to different machines. As a result they take extra time to handling material and setup machine. Reduction of change over time From the analysis section, it was apparent that the pressing machines were the most significant bottleneck. The production was impeded before the press by two to three days. There was a significant amount of work backlogged in front of each press machine. To reduce this wait time, the solution should focus on reducing the press change-over time. To accomplish this, two personnel would be required to work on each machine during the change-over process instead of one person. One person could do the preparation for the next order and the other could clean and wash the cylinders and stereo coverings from previous order and take them back to their storage locations, simultaneously. Since six different press machines exist at perfect profile centre, one operator could work between the machines and help the other machine operators during their setup process. This would mean that there would be no additional requirement to recruit and hire another operator. If two operators work on each machine during the setup process, the press would no longer be a bottleneck and the work queue in front of the press machines would be reduced, significantly. This would mean a much less wait time and a quicker response to meet the customers’ needs. Implementing 5S methodology To conduct a rapid change over, all fixtures and component varieties should be kept near to the operator so the operator does not require additional time to locate the needed components or fixtures, thus minimizing waste. The 5S methodology is an appropriate methodology to apply here to assist in organizing the work place. Essentially, the idea behind the 5S methodology was: by assigning everything a location, time is not wasted by looking for things. The 5S methodology, according to Peterson, was (Peterson 1998):  Separating: this means to separate the useful tools, materials, etc, from nonessential items and keep only the essentials. The nonessential tools should be kept in separate area or discarded.  Sorting: means arranging tools and equipment in an order that promotes work flow. Tools and equipment should be kept where they are needed and the process should be arranged in an order that eliminates extra motion.
  37. 37. 3  Shine: indicates the need to keep everything clean and neat. Cleaning must be part of the operators’ activity after each and every shift. Everything must be restored to its original places.  Standardizing: this means operating in a consistent and standardized manner. This will help everyone to know his or her responsibilities.  Sustaining: once all of the above 4S’s mentioned above are have been accomplished, it is necessary to stick to them and not allowing decline back to the old ways of doing things. At perfect profile centre there are some rules and regulations regarding cleanliness. Although, if perfect profile centre implements the 5S methodology and rearranges all components and equipment appropriately to reduce change-over time, the entire production process will be more efficient and less time consuming. Reduction of work in process (WIP) and wait time between the press and converter After the press process, label rolls had to wait approximately an hour to one day before being converted. The basic philosophy was that the next order to be converted was the one with the closest delivery date. At that point the labels were ready to be packed and shipped. The converting by itself was not a time consuming task but the wait time between the press and converter could be significant. This produced a rather large WIP in front of the converter. Another problem was that both the press and the converter produced some waste, such that the total waste was usually quite significant proportionally when considering small orders. In order to reduce the WIP inventory and the wait time between two processes, a special kind of converter could be used. It is attachable to the press machine, so that the two processes are combined into one process. The key point in lean production was to reduce the number of processes thereby reducing the wait time and WIP. The attachable converter has a setup time of about an hour. One of these attachable converters is already being used by perfect profile centre, but to increase the efficiency and reduce the lead time, two more were required. Since these converters had a long set up time, it would be more reasonable and appropriate to use them for high volume orders. For low volume orders, the old converter would be best used. The amount of waste in the new process would be less than the total amount of waste produced by each process. The merging of the two processes would create a one piece flow. In this way excess inventory
  38. 38. 3 and excess movement would be removed. Conclusions We found that the proposed model can improve Perfect profile centre manufacturing by 9% and working capital by around 41%. Based on our findings we are making the following recommendations. 1. Select all products which have a stable and a normally distributed demand, and consider them for the pull based proposed model. 2. Benchmark transportation times between various transporters and with agreed times to reduce the transportation time. 3. Ensure continuous monitoring of supplier lead times and lead times should not be allowed to exceed the agreed times. 4. Ensure continuous monitoring of internal lead. With the proposed pull system, the batch sizes of some raw materials would change and would reduce. This means that the new batch sizes would have to be renegotiated with the suppliers. The company can also think of pooling in orders from its other European factory for common raw materials. This would prevent the supplier from reducing its batch size of production but still can easily transport in smaller batches to individual factory. With these recommendations, it will be easier for the company to reduce its overall cycle time. References Rother, M. & Shook, J. (1999). Learning to See: value stream mapping to create value and eliminate muda. The Lean Enterprise Institute, Massachusetts. Liker, J.K. (2004). The Toyota Way: 14 Management Principles from the World's Greatest Manufacturer. McGraw-Hill, New York. Jonsson, P. & Mattsson, S.-A. (2003). Produktionslogistik. Studentlitteratur, Lund. Jonsson, P. & Mattsson, S.-A. (2011). Logistik: läran om effektiva materialflöden. Studentlitteratur, Lund. Olhager, J. (2000). Produktionsekonomi. Studentlitteratur, Lund. Lee, B. (2001) Lean Manufacturing. Wichita State University (Paper number 1 – Value Stream Mapping).
  39. 39. 3 Brunt, D. (2000) From Current State to Future State: Mapping the Steel to Component Supply Chain. International Journal of Logistics Research and Applications: A Leading Journal of Supply Chain Management. Volume 3, Issue 3, pg. 259-271 Jones, T., Womack, J. (1996) Lean Thinking: Banish Waste and Create Wealth in Your Corporation. New York: Simon & Schuster. Alukal, G. (2006, April). Building Blocks. Quality Progress. 39(4),87-88. Retrieved March 27,2008, from Wilson Web. Alukal, G., & Manos, A. (2008). How lean manufacturing can help your mold shop. Retrieved April 27, 2008, from http://www.moldmakingtechnology.comlarticles/100204.html Bellinger, G. (2004). Modeling and simulation: an introduction. Retrieved April 27, 2008, from http://www.systems-thinking.org/modsimlmodsim.htm Company XYZ. (2008). Capabilities. Retrieved April 26, 2008, from Company XYZ's website. Computer simulation. (2008). In Encyclopedia Britannica. Retrieved April 18, 2008, from Encyclopedia Britannica Online: http://www.britannica.comleb/article9001627 Fishwick, P. (1995). Computer simulation: the art and science ofdigital world construction. Retrieved April 18, 2008, from http://www.cis.ufl.edu/~fishwick/introsimlnodel0.html Askin R.G and Goldenberg J.B, ―Design and analysis of lean production systems”, Johan Wiley and Sons, New York, NY, USA, 2002 Bryman and Bell, Business Research Methods, 2nd Edition, 2007, Oxford University Press. Bicheno, J. (2004). The new lean toolbox : towards fast, flexible flow. Buckingham: PICSIE Books. Bicheno, J. (2009). Ny verktygslåda för Lean. För snabbt och flexibelt flöde. (M. Lindberg Howard, Övers.) Göteborg: Revere AB. Christopher Martin, 1992, Logistic and supply chain management, Pitman Publication. G. Corner, Lean Manufacturing for The Small Shop, Page 41, 2001. Ghauri & Gronhaug, Research Method in Business Studies: A Practical Guide, 3rd Edition, 2005, Page 265.
  40. 40. 4 John E. Wedel, Lead-time reduction in manufacturing: from initiation to realisation, Page 1-5, 1996 J.K. liker, Toyota Culture: the Heart and Soul of the Toyota Way, 2008

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