"LEAN MANUFACTURING PROCESS OF A COLOR INDUSTRY"

Abstract

Lean Manufacturing (LM) is a business strategy that was developed in Japan. The main role of lean manufacturing is to determine as well as to eliminate the waste. Companies implement LM to keep their competitiveness over their competitors by improving the manufacturing system’s productivity and quality enhancement of the product. The goal of this paper is to apply one of the most significant lean manufacturing techniques called Value Stream Mapping (VSM) to improve the production line of a color industry as a case of study. To achieve this goal, lean fundamental principles was implemented to construct VSM for identification and elimination of wastes by using team formation, product selection, conceptual design, and time-frame formulation through takt time calculation. Based on the future VSM, final results showed that by implementing some lean thinking techniques, Production Lead-time (PLT) decreased from 8.5 days to 6 days, and the value added time decreased from 68 minutes to 37 minutes.

Introduction

The concept of LM was proposed by a Japanese automotive company, Toyota, during 1950’s which was famously known as Toyota Production System (TPS). The first goal of TPS was to improve productivity as well as to decrease the cost by eliminating waste or non-value added activities. Lean manufacturing is one of the important steps that many major businesses in the United States have been attempting to implement in order to sustain their competitiveness in a rising global market. Main goal of this approach is on cost reduction by decreasing non-value activities. Based on the Toyota Production System, lean manufacturing tools and techniques such as just-in-time, cellular manufacturing, total productive maintenance, single-minute exchange of dies, and production smoothing have been consistently applied in different discrete manufacturing systems involving automotive, electronics. These improvements based on cost reduction are obtained by eliminating the wastes related to all activities done to deliver an order to a customer. Wastes include all activities that used resources by imposing cost to the product, but do not have a significant value on the customer. There are five steps to implement lean thinking in a company: 

1) Define value from the perspective of the customer, 

2) Determine the value streams, 

3) Achieve Flow, 

4) Schedule production using Pull, and 

5) Seek perfection through continuous improvement. 

Value stream includes all the specific activities (both value-added and non-value-added) needed to bring a particular product by implementing three important management skills of any business that are problem solving, information management and physical transformation. Lean manufacturing applied tools and approaches such as Just-In-Time (JIT), Total Productive Maintenance (TPM), Cellular Manufacturing and 5S. Moreover, lean accounting, as a coordinated approach, along with lean thinking provides administrators with reliable, accurate and timely information for decision-making. Hence implementation and control, of the lean system as new approach becomes for strategic management approach. The goal of this paper is to apply one of the most significant lean manufacturing techniques called Value Stream Mapping (VSM) to improve the production line of a color industry as a case of study.

 Methods

VSM includes a set of all activates (value added as well as non-value added) that are essential to bring a product through the main flows, starting with raw material, and ending with the customer [10]. The main goal of VSM is to find different types of wastes and trying to eliminate them. The first step is to select a specific product or product family as the target for improvement. The second step is that to develop a current state map that is mainly a snapshot capturing how processes are currently being done. The third step is to draw the future state map that is a picture of how the production process should be done after the wastes and inefficiencies have been removed. The future state map is created based on answering a collection of questions on topics relevant to efficiency as well as implementing technical issues related to the application of lean techniques. Finally, the suggested map is applied as a basis for making essential changes to the system. A brief explanation of the some various available lean methods and techniques are as follows: Cellular Manufacturing: systematize the whole process for a particular product or related products into a set or cell that it includes all the needed equipment, machines, and operators. Just-in Time: a method whereby a client’s request is treated such that the request is sent out backward from the last assembly of unprocessed material, thus ‘‘pulling’’ all the needed resources as at when needed. Kanban: the marking system for developing JIT production where by a visual signal helps flow by ‘pulling’ product through the process as required by the customer. Single minute exchange of dies (SMED): a changeover reduction technique. 5S: Concentrates on efficient workplace organization and standardized work events. This is a housekeeping method which entrusted control to the shop floor.

Project overview

A Color Factory is selected as a case study in this project. This company is a leading manufacturer of industrial and building paint. Since the products are produced according to the customer order, the layout of the factory is based on job shop system. The production line of different products (such as industrial paint, plastic paint, stone putty, and thinner) is located separately as well as the packaging section and laboratory. Having conducted the simulation, we found out that the production line of paint paste is a bottleneck. In addition, there are lots of reworks during the production process because of poor production control. Moreover, parts have to be transferred from machine to machine to complete the required operations. This situation decreases labor productivity and increases material handling cost. Therefore, these causes delay of orders, lower quality, less labor productivity, more waiting times, large Work in progress (WIP), longer material movement. To overcome these problems there is a need to identify the key areas, which are producing wastes, and to identify bottleneck operations.

To overcome the above problem we are using some Lean techniques and the techniques are listed below and briefly explained.

1. Value stream Mapping
2. 5s Implementation
3. Simulation 
4. Kanban and
5. Keizen method

The above 5 method we are implementing in this project to overcome the above problems.

1. VALUE STREAM MAPPING (VSM):

     Firm’s efficiency and competence are two significant challenges in today’s global market that have motivated many manufacturing firms to plan novel manufacturing management strategy. The most censorious issue faced by manufacturers today is how to deliver products or materials to customer at low cost and good quality. One of the successful management approaches is lean manufacturing system that has taken by many manufacturing companies in different ways. The concept of lean system is extract from Japanese manufacturing system.    During 1950’s Toyota was famously known as Toyota production system(TPS). The first goal of TPS was to upgrade productivity as well as to decrease the cost by eliminating waste in the form of non-value added activities. 

Lean is a one of the business strategy for the elimination of waste with in the manufacturing system. In today’s world most of the companies are using this strategy in order to sustain the competence in a rising global market. Main goal of approach is on cost reduction by reducing non-value activities. Based on the Toyota production system, lean manufacturing tools and techniques such as just-in-time, cellular manufacturing total productive maintenance, single minute exchange of dies, and production smoothing have been consistently applied in different discrete manufacturing systems involving automotive electronics. These improvements are based on cost reduction and are obtained by eliminating the wastes related to all value and non-value added activities done to deliver an order to a customer. Wastes include all activities that used resources by imposing cost to the product, but do not have an important value on the customer. There are five steps to implement lean thinking in a company:

   1) Define value from the perspective of the customer                                       

2) Identify the value stream

3) Achieve flow of the product

4) Schedule production using pull, and

5) Strive for perfection through continuous improvement.

 Value stream includes all the specific activities (both value and non-value added) needed to bring a particular product by implementing three significant management skills of any firm that are problem solving, information management and physical transformation. Lean manufacturing applied tools and approach such as just-in-time (JIT), total productive maintenance (TPM), cellular manufacturing and 5s. The main target of this paper is to develop a value stream mapping(VSM), which is becoming a useful tool for implementing lean manufacturing in actual production line of the color industry.

VSM includes all the set of activities that are involved in producing a product, all the processes right from the material to delivering the finished product or service to the customer. The main objective of VSM is to fetch and eliminate wastes. VSM includes the following steps:

• Step 1: Targeting a specific product or a product group or task.
• Step 2:  Developing a current state map, the overview of how the processes are going on currently. 
• Step 3: Then the wastes are reduced and eliminated.
• Step 4: Developing a future state map, forming a picture of how processes are done after eliminating the wastes. 

                  VSM creates a direction and vision to the company. It studies and analyses all the processes that are involved in current functioning. Then an ideal stream of processes is created to aim for and work towards. VSM cannot be done on multiple products, as it results in overloaded the data. A particular product or group is highlighted and improved. If there is a case with large number of individual products, tools are used to find the similarities amongst the products and make families.

                  VSM is not a virtual process that runs on computer in office. It is actually done at gemba (work place). VSM should include exactly what happens in real data such as stock level, lead times, change over time, setup time, quality level. This will help in further improving the process.

3.1) CURRENT STATE MAPPING:

The whole present state map is studied using Rother and Shook methods. The catalogued level information is collected prior to beginning of the processes, such as, cycle times, setup times, convert times, lead times, quantity of employees. The figure 1 shows the current state map that is built. The small boxes in the figure depicts the progression of the process, the number of shifts is the number of boxes in each processes. Additionally, data box is included under every process which includes CO time, CT, machine reliability, number of shifts. All the processing times and installing times are gained by middling the past data. The figure 1 also shows a time line under it. This time line has two parts, the first part shows the lead time in days. This lead time is calculated by adding all the lead times earlier. Lead time is approximately 8.5 days. The second part of the timeline is the, processing time of the tasks involved. It is found to be approximately 68 minutes. 

Figure 1: Current state map

3.2) FUTURE STATE MAP:

       In current state map, the lead time of the production line is taking 8.5days and processing time is around 68minutes. To reduce this lead time and processing time, need to follow some techniques they are: 5s Implementation, continuous improvement, Kanban method.

      In order to apply above techniques initially we need to find the problems where the process is taking more time. In current state mapping, the big mixture and delpak mixture stations have the most cycle time with 14 and 13 minutes respectively that makes WIP (Work in Process) before the station. Continuous flow is applied for producing products using batch size of one. Following that, Kanban method was applied to eliminate waste from inventory and over production. We can eliminate the necessity for physical inventories. Kanban maintains inventory levels that mean a signal is sent to produce and deliver a new shipment as material is consumed. These signals are followed through replenishment cycle and bring extraordinary visibility to suppliers and buyers.

        In addition, 5s principles (sort, segregate, shine, standardize, sustain) were implemented to eliminate waste, that provides the solution from a poorly organized work area. 5s programs are usually implemented by small teams working together to get materials closer to operations, right at worker’s fingertips and organized and labeled to facilitate operations with the smallest amount of wasted time and materials. 

             Future process mapping and improvement is shown in the figure2. In this map, the permil machines and big mixer as well as testing and weighting units were combined to reduced non-value added time during processes. Appliance of 5s techniques, Kanban method, continuous flow, result in effective organization of the workplace, reduction of work environment, elimination of losses connected with failures and breaks, improvement of the quality and safety of the work. The information and communication flow between processing lines improved by applying VSM to the current state. So added time r that lead time has gone from 8.5 days to 6 days, and value added time reduced from 68 minutes to 37 minutes as shown in figure2.

2. 5S Implementation:

5s is workplace organization methodology that uses list of five Japanese words

Sorting 

Straightening 

Systematic cleaning 

Standardizing 

Sustaining 

1. Sorting (seiri)

• Eliminate all unnecessary tools, parts and instructions.
• Keep only essential items and eliminate what is not required.
• Prioritizing things per requirements and keeping them in easily- accessible places
• Everything else is stored or discarded

2. Straightening or setting in order/ stabilize (seiton)

• There should be a place for everything and everything should be in its place.
• The place for each item should be clearly labeled or demarcated.
• Items should be arranged in a manner that promotes efficient work flow, with equipment used most often being the most easily accessible

3. Shining or systematic cleaning (Seiso)

• Clean the workspace and all equipment, and keep it clean, tidy and organized.
• At the end of each shift, clean the work area and be sure everything is restored  to its place.
• Maintaining cleanliness should be part of the daily work – not an occasional activity initiated when things get too messy

4. Standardizing (seiketsu)

• All work stations for a particular job should be identical 
• All employees doing the same job should be able to work in any section with the same tools that are in the same location in every station 
• Everyone should know exactly what his or her responsibilities are for adhering to the first 3 S’s

5. Sustaining  the discipline or self-discipline (shitsuke)

• Maintain and review standards
• Maintain focus on this new way and do not allow a gradual decline back to the old ways
• While thinking about the new way, also be thinking about yet better ways.

6. Benefits of 5s

• Improves organizational efficiency
• Reduces waste in all forms
• Cuts down employee frustration when “ the system doesn’t  work”
• Improves speed and quality of work performance
• Improves safety
• Creates a visually attractive environment 

In this project 5s principles were implemented to eliminates  the results from a poorly organized from work area such as permil machines and big mixer are put together in the same shop floor where as testing , weighting are different process in value stream mapping (VSM) both are in same floor in future VSM. By change the working process we can standardizing the work at the same time we can reduces waste of time in process, Increases speed and quantity 

3. Simulation

Simulation, like most analysis methods, involves systems and models of them. So in this section, we give you some examples of models and describe options for studying them to learn about corresponding system.

Arena is an easy-to-use, powerful modeling and simulation software tool that allows the user to construct a simulation model and run experiments on the model. The software generates several reports as a result of a simulation run.

In this project we are implementing a sample model of simulation which helps us to find out the productivity. We simulated both the model current painting process that they doing in the plant. By using the current value streaming we took the data, from that we run the process for the span of 30 days with 8 hours shift. From the simulation results we found that 9 shipments can make in a month, and the 2 shipments are in the processing. 

Current simulation model

Current Simulation Model Results

Number out	9
Value Added time Entity 1	132.97
Total Time	132.97
Number in	11
Number Out	9
WIP	1.7621

Instantaneous Utilization

Big	0.00300926
Delpak	0.00324074
Permil	0.00231481
Testing validate	0.00229167
Weightin machine	0.00208333

Total Number Seized

Big	10
Delpak	11
Permil	10
Testing validate	9
Weightin machine	9

By using future state mapping we developed a new simulation model by validating that we got good productivity while compared with current simulation model.

In the future simulation we got almost 11 shipments we can make in 30 days with 8 hours shift per day.

Future simulation model

Future simulation results

Number Out	11
Entity 1 Value added time	72.2833
Entity 1 wait time	10.9023
Total Time	83.1856
Number In	12
Number Out	11
WIP	1.3771
Number Waiting at staging shipping queue	0.1858
Waiting Time at staging shipping	11.1472

Instantaneous Utilization

Delpak	0.00138889
Personal machine	0.0019444
Staging	0.3866
Testing	0.00138889

By using feature simulation model results there is a lot of improvement in the productivity by comparing current simulation model results. In current simulation model the productivity is  9 shipments they can do  in 30 working days with 8hrs shift per day and  2 shipment are in  progress 

In feature simulation we improved the process by collaborating 2 process in 1 process and to transfers the painted parts we use automated process in a simple and easy way for faster productivity and here collaborating testing and weighting together first the part comes from personal machine and big mixture we do testing for the part at a time we do weighting by this we can improve the time between testing and weighting. By comparing current state and future state results we can make 2 more shipments in a better and easy way

4) Kanban Method:

The Kanban system was developed over 20 years ago by the Vice President of Toyota Production System, Mr. Taiichi Ohno. It is an inventory - control system to control the supply chain and improving the efficiency to achieve the goal of Just In Time (JIT).

It is a Japanese manufacturing system in which a card is used to maintain the supply of components in the production process and card consists of  various information necessary for complete production cycle. The term Kanban means ‘signal’ or ‘sign’ that initiates the replenishment of items as a visual indicator.

4.1) TYPES OF KANBAN SYSTEM

There are two broad categories of Kanban system: Production Kanban and Withdrawal (conveyance) Kanban.

Production Kanban

The aim of production Kanban is to release an order to the preceding stage to build the lot size indicated on the card. It is referred to as P- Kanban and carried by the containers associated with it.

Withdrawal (conveyance) Kanban

It involves the transportation of the full containers to the downstream work station. It is referred to as T- Kanban and carried by the containers associated with the process.

4.2) GOALS OF KANBAN SYSTEM

• It reduces the cost by eliminating the waste or scrap items.
• It is responsible for creating worksite which is flexible for ultimate changes.
• It facilitates method to achieve quality control.
• It designs worksite in accordance to human dignity, mutual trust & support which paves way for the workers to achieve maximum potential.
• It is often used in automotive industry with low production sectors aiming for a higher production rates simultaneously.
• The Work In Progress has lead to the idea of Kanban to implement pull type control in production systems.
• The control of pull /push is established by the Kanban. In push type policy, the parts are produced within each individual production stages.

4.3) RULES OF KANBAN SYSTEM

The following six conditions are mentioned below,

• Downstream processes may only withdraw items in the precise amounts specified on the Kanban.
• Upstream processes may only send items downstream in the precise amounts and sequences specified by the Kanban.
• No items are made or moved without a Kanban.
• A Kanban must accompany each item at all times.
• Defects and incorrect amounts are never sent to the next downstream process.
• The number of Kanbans should be monitored carefully to reveal problems and opportunities for improvement.

4. IMPLEMENTATION OF KANBAN SYSTEM

The common way of using the Kanban system is by painting square boxes on the job floor between the work areas. The layout of the color industry is based on the job shop system. Once the work area 1 is done with the process, the square is empty. The cards are used as replacement of the painted squares. The two cards used are Demand card and Travel card. The size of the Kanban plays a major role in this system.  By simulation, the production line of the paint paste is identified as a bottle neck.

Demand card

The demand card consists of information required for the work area. It travels throughout  the work areas only. On the card the job details like part number, quantity, operation number, previous work area and so on. The reverse of the card consists of information about the parts needed to complete the operation. The key factor is identification of bottle neck and their type. Here it is Paint paste respectively. The order of the demand card decides the priority of the product to be processed first. The batch size remains the same whereas the demand card may vary according to the production.

	ARTICLE	QUANTITY	STORE
	1
	2
	3
	4
	5
	6
	7
	8

	Demand card
	Parent article no                    }		=
	Sub. Assembly no                       }		=
	Quantity Required           }		=
	Operation no		=
	Description		=

Travel card

The travel cards are effective as an inspection record or work order. It comes from the management directly whereas the demand cards will live on the shop floor in a box. It contains the information related to a unique batch of their representation. It includes batch number, part number, required date and the reverse of the card will be the inspection record.

The travel card is produced only for its needs. The production is done for products with both demand card and travel card. It is a batch ticket and flow through the job floor system recording the product history. Thus the number of travel card produced will limit the products made and so over production is limited.

• The production control limits set for the shop floor can be achieved.
• If breakdown occurs new jobs cannot be started which is true for quality and break down problems.
• Work in Progress is controlled by limiting the total number of demand cards available at a time.

5. KAIZEN SYSTEM

INTRODUCTION

The word Kaizen is a Japanese term means ‘Continuous Improvement’ aiming for a better change. (Kai – Continuous; Zen – Improvement). The concept was introduced by Dr.W.Edwards Deming. The goal is to do it better, make it better and improve it better. The various components such as quality circles, automation, suggestion systems, just-in-time delivery, Kanban and 5’s are all included in Kaizen system. It involves setting standards and then continually improving those standards.

TYPES OF KAIZEN

The major three types of Kaizen are Teaian kaizen - Individual Versus Teamed , Quality Circles - Day-to-Day Versus Special Event, Special events: Kaizen Blitz technique - Large-Scale Vs. Small-Scale Improvement. 

OBJECTIVES OF KAIZEN

• It observes the complete process from start to the end.
• It identifies the problems in the industry
• It generates idea and designs action plan to overcome those problems.
• The process of implementation and analysing the process.
• It achieves the final results and solutions in accordance to quality and quantity.

IMPLEMENTATION OF KAIZEN

The process of Kaizen can be defined as Plan, Do, Check and Act. The most important step is the identification of problems, remedial measures and evaluating the corrective actions.

Identification of problems

The separate paint shop is to be provided to avoid the paint particles being spread all over the space available. The improper handling and inventory of materials is to be avoided which might increase the production time. The safety measures are to be maintained properly and also the waste products obtained during the production process should be disposed of in good manner to avoid any environmental hazards.

Remedial measures

The following strategy is done as a remedial measure in the color industry with paint paste as a bottle neck.

	PROBLEMS	CAUSE	ACTION
	Labour inefficiency	Bad working Condition	Provide good working condition
	stoppage of work	Spread paint particles all over the shop	Restriction to flow the particles
	Incomplete target in painting	Waste of time in refilling paint gun	Use advanced method
	Health problem	Bad working condition	Provide good working condition
	Loss in production	Breakdown in work	Remove breakdown in work
	Loss in working time	Breakdown in work	Remove breakdown in work
	Increase in production lead time	Breakdown in work	Remove breakdown in work

Evaluating the corrective actions

 The evaluation of the corrective action depicts the improvement of the color industry productivity simultaneously.

	PROBLEMS	BEFORE KAIZEN	AFTER KAIZEN
	Labour inefficiency	less	more
	Stoppage Of work	more	Less
	Loss in Production	more	Less
	Loss in Working time	more	Less
	Health and accident problems	more	very less
	Improper Inventory	more	very less
	Improper Handling material	more	very less

Conclusion: 

The main goal of this paper was to develop a Value Stream Mapping (VSM), which is becoming a useful tool for implementing lean manufacturing in actual production settings. The results are presented in the form of current and future process mapping and improvement is shown in the reduction in valued added time and production lead time. In the future state map, the permil machines and big mixer as well as testing and weighting units were combined to

reduce non-value added time during processes. Implementation of 5s techniques, Kanban method, continuous flow, result in effective organization of the workplace, reduction of work’s environment, elimination of losses connected with failures and breaks, improvement of the quality and safety of work. Supermarkets are placed between processes to reduce inventory wastages during process and to turn process from build to stock to make to order. The information and communication flow between processing lines improved by scheduling pacemaker in the process as well process turned from push to pull by Kanban system. On this research we have made some sizeable improvements. Production Lead-time (PLT) has gone from 8.5 days to 6 days, and the value added time decrease from 68 minutes to 37 minutes.

The goal of this paper was to develop a value stream map for a color industry to determine and eliminate the wastes that did not add value to the final product. It also aimed to reducing lead time and value added time to increase the total throughput. Based on future VSM, final result showed that by implementing some lean manufacturing techniques such as 5S, Kanban method, Kaizen and so on Production Lead-time (PLT) decreased from 8.5 days to 6 days, and the value added time decreased from 68 minutes to 37 minutes. More investigation can be done by combining the VSM and computer simulation to evaluate more effective factors that have a significant effect on the total throughput based on decreasing wastes.

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