Intro and Lit Rew

7/31/2019 Intro and Lit Rew

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CHAPTER I

LEAN MANUFACTURING

1.1 THE HISTORY OF LEAN

After World War I Japanese manufactures were faced with the dilemma of

vast shortages of material, financial, and human resources. The problems that Japanese

manufacturers were faced with differed from those of their Western counterparts. These

conditions resulted in the birth of the "lean" manufacturing concept. Toyota Motor

Company, led by its president Toyoda recognized that American automakers of that era

were out-producing their Japanese counterparts; in the mid-1940's American companies

were outperforming their Japanese counterparts by a factor of ten. In order to make a

move toward improvement early Japanese leaders such as Toyoda Kichiro, Shigeo

Shingo, and Taichi Ohno devised a new, disciplined, process-oriented system, which is

known today as the "Toyota Production System," or "Lean Manufacturing." Taichi

Ohno, who was given the task of developing a system that would enhance productivity

at Toyota is generally considered to be the primary force behind this system. Ohno

drew upon some ideas from the West, and particularly from Henry Ford's book "Today

and Tomorrow." Ford's moving assembly line of continuously flowing material formed

the basis for the Toyota Production System. After some experimentation, the Toyota

Production System was developed and refined between 1945 and 1970, and is still

growing today all over the world. The basic underlying idea of this system is to

minimize the consumption of resources that add no value to a product. In order to

compete in today's fiercely competitive market, US manufacturers have come to realize

that the traditional mass production concept has to be adapted to the new ideas of lean

manufacturing. A study that was done at the Massachusetts Institute of Technology of

the movement from mass production toward lean manufacturing, as explained in the

book ''The Machine That Changed the World" by Womack and Jones (1996),

awoke the US manufacturers from their sleep. The study underscored the great success


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of Toyota at NUMMI (New United Motor Manufacturing Inc.) and brought out the

huge gap that existed between the Japanese and Western automotive industry. The ideas

came to be adopted in the US because the Japanese companies developed, produced and

distributed products with half or less human effort, capital investment, floor space,

tools, materials, time, and overall expense.

The road to transition American manufacturers into lean organizations has taken many

decades of development. The origins of lean can be traced back to Kiichiro Toyodas

vision of just-in-time part delivery in the 1930s. The system of lean production was

implemented by Eiji Toyoda and Taiichi Ohno at the Toyota Motor Company in Japan

in the 1950s. However, it wasnt until books such as Japanese Manufacturing

Techniques by Schonberger (1982) and Zero Inventories by Hall (1983) were published

that the concept of lean manufacturing was considered to be applicable to organizations

outside the Japanese automobile industry. When Womack et al. (1990) published The

Machine that Changed the World, a new era in the approach to manufacturing systems

design was launched. In the mid- 1980s, in response to several governments concerns

about the health of their automobile industries, the Massachusetts Institute of

Technology created the International Motor Vehicle Program (IMVP). It was one of

IMVPs researchers, John Krafcik, who first used the term lean production to

describe the production system that used significantly fewer resources compared with

the widely accepted system of mass production.

The fundamental of lean production is to identify and eliminate wastes, all work of an

enterprise can classified into three parts, the first is value-added work includes essential

activities that add value to a project in a way the customer is willing to pay for. The

second is incidental work includes the auxiliary activities that dont necessarily add

value, but must be done to support value-added work. The third is non value-added

work or waste includes non-essential activities that add time, effort, cost, but no value,

which we are familiar in production site that has not implemented lean production

including superfluous inventory, unnecessary transportation, waiting, excess

processing, wasted motion and products with defects.


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Lean has proven to be an effective management philosophy for improving businesses

in a competitive market by eliminating waste and improving operations. An impact of

implementing lean projects is the rapid reduction in inventory levels, which gives

management the false impression that profits are decreasing while workers on the shop

floor observe improvements in operations and increased floor space.

Many major businesses in the United States have been trying to adopt lean

manufacturing principles in order to stay competitive in a global market that is

characterized by increased competition and customer expectations. Many businesses

have found lean philosophy to be the potential solution over other improvement

methodologies and approaches for businesses trying to focus on waste elimination andproducing products that meet customer expectations in terms of quality and on-time

delivery. Although the lean approach is promising, the progress of adopting it by

manufacturing companies has been progressing slowly in the US and Europe, according

to Lian and Landeghem (2007), because traditional manufacturers, from both

operational and financial perspectives, question the effectiveness of lean

transformation.

From the operational point of view, traditional manufacturers are reluctant to

implement lean ideas because they cannot quantify and project the benefits that they

can gain by implementing it. As Detty and Yingling (2000) state: The decision to

implement lean manufacturing, as just described, is a difficult one because of the

substantial differences between traditional and lean manufacturing systems in employee

management, plant layout, material and information flow systems, and production

scheduling/control methods. These differences make it difficult for organizations that

have historically relied on traditional manufacturing methods to predict the magnitude

of the benefits to be achieved by implementing lean principles in their unique

circumstances. As a result, the decision whether or not to adopt lean manufacturing

techniques often must be based on a combination of faith in the lean manufacturing

philosophy, the reported experiences of others who have previously adopted these

principles, and general rules of thumb on anticipated benefits. For many management

teams, such faith-based justification is insufficient to convince them to adopt lean

concepts.


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From the financial point of view, one of the wastes that lean implementation eliminates

quickly when applied is excess inventory. Lower inventory levels negatively affect the

bottom line of the financial statement and a misleading impression is taken that lean is

not improving the business and should be stopped. As a result of mis-interpreting lean

operationally and financially, some managers stand against any progress taken for lean

implementation and improvement initiatives.

2.1 The definition of VSM

Value stream mapping is a technique or tool with a pencil and paper that helps people

to see and understand the flow of material and information as a product makes its way

through the value stream. The elements of VSM include customer loop, productioncontrol, supplier loop, manufacturing loop, information flow and lead time data bar

with critical path that make us have a full view of the whole supply chain from

customers requirements to suppliers delivery.

2.2 Why do VSM First

Value stream mapping helps us understand where we are (Current State), where we

want to go (Future State) and map a route to get there (Implementation Plan), which can

create a high-level look at total efficiency, not the independent efficiencies of individual

works or departments, visually show three flows - material flow, product

flow and information flow to identify improvement opportunities, and help identify

applicable lean improvement tools and plan for deployment. The practices of

enterprises have successfully implemented lean production prove that VSM can

eliminate 50% waste process/steps, shorten cycle time by 30%, reduce variation from

30% to 5% and improve product quality greatly. So we should implement lean

production first from VSM.

1.2 LEAN MANUFACTURING PRINCIPLES


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Lean Manufacturing focuses on eliminating waste while delivering quality

products at the lowest cost to the manufacturer and consumer. Lean methods typically

lead to significant environmental benefits. Lean manufacturing is a management

philosophy focusing on reduction of the 7 wastes (Over-production, Waiting time,

Transportation, Over-processing, Inventory, Motion and Scrap) in manufactured

products. By eliminating waste, quality is improved, production time is reduced, and

cost is reduced. Lean "tools" include constant process analysis (kaizen), "pull"

production (by means of kanban), and mistake-proofing (poke yoke).

One crucial insight is that most costs are assigned when a product is designed.

Often an engineer will specify familiar, safe materials and processes rather than

inexpensive, efficient ones. This reduces project risk, that is, the cost to the engineer,

while increasing financial risks, and decreasing profits. Good organizations develop and

review checklists to review product designs.

The Five lean manufacturing principles given by Burton and Boeder

(2003) are as under:

1. Accurately specific values from the customer's perspective for both products and

services.

2. Identify the value stream for products and services and remove non-value-adding

waste along the value stream.

3. Make the product and services flow without interruption across the value stream.

4. Authorize production of products and services based on pull by customer.

5. Strive the perfection by constantly removing laters of waste.

Thus, lean is basically all about getting the right things, to the right place, at the

right time, in the right quantity while minimizing waste and being flexible and

open to change.


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Value: Define value from the standpoint of the customer. However, in reality, the

final customer is the only one who can specify the value of a specific product or service

by paying a price for it.

Value stream: View your product delivery system as a continuous flow ofprocesses

that add value to the product.

Flow: The product should constantly be moving through the value stream towards

the customer at the pace of demand.

Pull: Product should be pulled through the value stream at the customers demand

rather than being pushed on to the customer

Perfection: The never-ending pursuit of eliminating waste in the system such that

the products can flow seamlessly through the value stream at the rate of demand.

OVERVIEW OF LEAN MANUFACTURING

According to Womack and Jones (2003), who are internationally renowned

management analysts, there are five basic principles a company or organization should

follow in order to embrace the lean thinking characteristics. The major goal of those

principles is to reduce cost by eliminating waste. Waste consists of all activities that do

not add value from the customers point of view. Reducing cost is also emphasized by

Narasimhan, Parthasarathy, and Narayan (2007). The Womack and Jones principles

are:

1. Specifying value by determining what the customer values in a product or services.

2. Defining the value stream for a specific product or product family along a value

stream and eliminating non-value-added activities (NVA) as perceived by the customer

so that the product or service is delivered to the customer in the most efficient way.


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3. Getting the product or service to flow by creating continuous flow for the value-

added activities (VA), and replacing batch and queue with single-piece flow.

4. Creating a pull mechanism from the customer by making what the customer wants

and when they want it by establishing takt time, and regulating inventories.

5. Striving for perfection through continuous lean journey.

There are seven types of waste (muda in Japanese) that lean focuses on reducing, if not

eliminating (Narasimhan et al., 2007; MCS Media, 2006; El-Haik & Al-Aomar, 2006).

They are: overproduction, waiting time, transportation, over-processing, inventory,

motion and scrap. Figure 1 shows those sources of waste graphically. As a result of

waste reduction, improvements emerge in reduction of operating cost, productivity,

quality and on-time delivery of products (Narasimhan et al., 2007)

Sources of waste in any production system

Narasimhan et al., (2007); MCS Media (2006);and El-Haik and Al-Aomar (2006)

describe each source of waste as :


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Defects: making mistakes in the production process that results in generating

reworked or scrapped products

Inventory: the buildup of excessive inventory in the form of raw material, work-

in-process, and finished items

Motion: unnecessary movements of workers or machines before, after, or during

processing

Over-processing: unnecessary and non-value added usage or processing of

equipment, tools, and materials

Over-production: producing more than required quantities of products

Transportation: unnecessary and excessive movement of materials or parts

within the production line, the warehouse, or the storage area

Waiting: parts or materials waiting in queues for being processed

5. Creating Flow: Introducing Pull System Controls

What Is Pull?

Most target improvements retain the traditional push system. This is especially true of

upstream, shared, resources. The lean future state is based on pulling work through the

system, at the required rate, rather than pushing.

The first question to ask about this future state is, How does anyone know what to

produce? In a push system,everyone has a schedule, a work list, or some other kind of

information that tells what and how many. In the simplest versionof a push system, the

requirement is simply to carry out a standard operation on whatever is first in the WIP

queue. The pullsystem is really not that different. Instead of working constantly on what

is in the upstream queue, or following a schedule,the operator fills containers that arrive

from the downstream operation, or produces a quantity equal to the number of


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between the bottleneck and shipping, then there will some other point downstream of

the bottleneck where continuous flow becomes possible, and this pacemaker

operation is then the logical point to schedule the entire process. An additional

complication might exist when demand varies over time. This means that the calculated

rate of flow, or the takt of the system, needs to vary. There are a number of solutions to

this that can be used to make the pull system work, and they are generally familiar.

They include putting more inventory between operations or in finished goods, using

overtime to complete the days requirements, adding operators to cells, using additional

pieces of equipment at operations that are at capacity, and so forth. Since the situation is

not expected to be permanent, these changes must be implemented in a flexible manner.

Below, the concept of load levelling is also discussed.

Some Advantages of Pull over Push

Of course, converting traditional manufacturing to demand-based manufacturing is not

quite as simple as pulling instead of pushing. While a push system bases production

authorization on a calculation of what will be needed in the future, if everything goes

according to plan, pull authorizes production only when material is actually needed

(with a calculation of when this material should be made, which assumes that theproducing operation will function as planned). Neither system deliberately tries to

create too much inventory. But whereas a push system frequently creates too much, and

in some places too little, a pull system is most likely to produce too little (or

equivalently, too late) when it fails.

As indicated above, balance and reliability are important to a successful pull system. As

well, shared resources must be able to serve all value streams at the required rate. As

we have seen, this requires substantially faster setups. Consider the steps that need to be

taken to convert a system from push to pull, and simultaneously to reduce the cost of

production (since pull by itself is not necessarily a lower-cost mode of production).

In trying to pull, it will quickly become apparent that predictability and reliability are

key factors in meeting demand. It is, of course, just as important for push systems to be

reliable, if they are to be cost effective. However, it is because of the larger amounts of

inventory usually contained in push systems that reliability receives less attention.Given sufficient inventory, and a tendency to ignore the costs of inventory, the sporadic


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replenishment of inventory appears to be adequate in push systems. As soon as

inventory is only produced to replace what has already been consumed, reliability

becomes much more important, since there will be constant shortages under a system

that produces sporadically and unpredictably. With a high degree of reliability, it is

possible to calculate lead times, and hence the number of productionauthorizations

(kanbans) that the system requires to function acceptably.

Predictability will not, by itself, reduce costs sufficiently to justify instituting a pull

system (because a predictable push system holds the same level of inventory, and may

even function more smoothly). The next requirement for a pull system is balance. This

means that each step in the process takes the same time to complete a unit of

production. When we say the same time, there is some room for variation if the

system produces a family of parts. The accepted guideline for variation is a 30%

spread from the shortest to the longest. A family of products is produced by a group of

production centers when there is insufficient business for just one product. In a pull

system, product design and sales will try to achieve, as close as possible, a much

narrower variation in time than the outside limit of 30%. Here a significant distinction

between the push approach and the pull approach is evident. Push measures utilization,

whereas pull measures flow. This explains the two control systems very different

approaches to what is wasteful, and ultimately the lower cost of pull systems.

The final requirement of cost reduction through pull is stability. While the market may

be chaotic, it is possible to impose a large amount of order through leveling the

production requirements. This leads to a highly stable load on the system, and

furthermore, a repeatable pattern of demand. A pull system becomes highly responsive

when it is capable of short runs. This is achieved through quick setup, productive

maintenance, multi-skilled operators, and so forth. In this way, all products will be

available at all times, and whatever the customer uses will be replaced in quick order.

On the other side of the equation, there will be an attempt to impose some sort of order

on the chaos of the market through rewarding steady demand (rather than looking for

larger orders than the market really needs through volume discounts, which the push

system strives for).


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Assuming that everything works exactly as planned, there ought not to be any

significant difference, from the point of view of inventory levels, between pull and

push. In fact, if the planning horizon is short enough, push would appear to turn into a

roundabout pull system. But this assumption is rarely correct. The reason push systems

tend to create excess inventory is that the penalty for failure is not immediately

apparent. Few managers complain of too much inventory; too little, on the other hand,

is cause for serious concern, because shipments will be late, and customers dissatisfied.

So why does anyone want to move to a pull system? The clear cost advantages outlined

above are one reason. There is also an advantage in quality level, because the system

simply will not work without flawless quality (since scrap will throw off the timing of

the pull signal). Therefore, assuming that a pull system can be set up that delivers

unfailingly on time, there is a clear competitive advantage. So one of the key

advantages of pull is that it forces a producer to constantly strive for perfection. A

producer using a push system is only forced to improve if it stands to lose significant

business due to high cost and low quality. One of the ironies of push systems is that

they are also poor at on time delivery, despite an excess of inventory because the

inventory on hand is often not what the customer wants.

1.3 GLOBAL COMPITITIVENESS AND LEAN MANUFACTURING

International competition and customer demands are forcing radical changes to

occur in manufacturing. As a result, companies worldwide that are realizing the

importance of being part of the global market are searching for operational methods to

increase their competitive power through the use of innovative production systems.

Traditional manufacturing paradigms are being challenged and new manufacturing

principles are being developed. Terms such as: lean manufacturing, world-class

manufacturing, and agile manufacturing have emerged. Firms have given increased


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emphasis to delivering products, that are needed by customers, faster than their

competition, and meeting or exceeding "best-in-class" quality requirements.

As more manufacturers struggle with global markets,

competition from low-cost countries and faltering home economies, the attention of

many manufacturers has turned to adopt lean philosophy to get benefits of eliminating

non-value-added waste across value stream, which positively impacts profitability and

creates value for customers, which in turn leads to competitive advantage.

A majority of organization are either in the process of applying lean

thinking or considering making the leap to embracing the lean thinking. What is it about

this infatuation with lean thinking that has such a powerful influence on organization?

In short the benefits of eliminating non-value-added waste across value stream are

significant as it positively impacts profitability and creates value for customers, which

in turn leads to competitive advantage.. Financial performance for an organization can

be impacted from both a cost perspective and a growth perspective. The ability to create

double-digit growth in sales has showed for most organizations in todays economy.

Thus the emphasis has shifted to improving gross margins through cost reduction.

There is such a large untapped amount of cost reduction that can be generated by

eliminating waste across value streams. It is not uncommon to have ratios of 5 to 30%

value added contents in value stream components. That means there is the opportunity

to eliminate 70 to 95% of waste in the value stream. Various benefits of lean as given

by Burton and Boeder (2003) are illustrated below:

Elements Benefits

Capacity 10 to 20% gains in capacity by optimizing bottlenecks

Inventory Reduction of 30 to 40 % in inventory

Cycle time Throughput time reduced by 50 to 75%

Lead time Reduction of 50% in order fulfillment

Product development time Reduction of 35 to 50% in development time

Space 35 to 50% gain space reduction

First-pass yield 5 to 15% increase in first-pass yield

Service Delivery performance of 99%

Table 1.1 Lean Benefits


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1.4 LEAN MANUFACTURING TOOLS AND

TECHNIQUIES

Various key Lean tools and techniques are discussed one by one below and shown in

diagram below. Key lean tools are:

Kaizen

5S

Total Productive Maintenance (TPM)

Cellular Manufacturing / One-Piece Flow Systems

Just-In-Time (JIT) Production Systems/ Kanban

Production Smoothing

Standardization of Work

Six Sigma

Single minute exchange of die (SMED)

Value Stream Mapping

These are shown in figure below:

Fig 1.1 Key Lean Tools


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The Structure of VSM Based Lean Production System


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1.1.4 Kaizen


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Kaizen or rapid improvement processes are often considered to be the building

block of all lean production methods. Kaizen focuses on eliminating waste in the

targeted systems and processes of an organization, improving productivity, and

achieving sustained continual improvement. This philosophy implies that small,incremental changes routinely applied and sustained over a long period result in

significant improvements. The kaizen strategy aims to involve workers from multiple

functions and levels in the organization in working together to address a problem or

improve a particular process. The team uses analytical techniques, such as Value

Stream Mapping, to quickly identify opportunities to eliminate waste in a targeted

process. The team works to rapidly implement chosen improvements (often within 72

hours of initiating the kaizen event), typically focusing on ways that do not involve

large capital outlays. Periodic follow-up events aim to ensure that the improvements

from the kaizen blitz are sustained over time. Kaizen can be used as an implementation

tool for most of the other lean methods.

1.4.2 5S

5S is a system to reduce waste and optimize productivity through maintaining

an orderly workplace and using visual cues to achieve more consistent operational

results. The SS pillars, Sort (Seiri), Set in Order (Seiton), Shine (Seiso), Standardize

(Seiketsu), and Sustain (Shitsuke), provide a method for organizing, cleaning,

developing, and sustaining a productive work environment. In the daily work of a

company, routines that maintain organization and orderliness are essential to a smooth

and efficient flow of activities. This lean method encourages workers to improve their

working conditions and facilitates their efforts to reduce waste, unplanned downtime,

and in-process inventory. SS provides the foundation on which other lean methods,

such as total productive maintenance, cellular manufacturing, just-in-time production,

and Six Sigma, can be introduced.

1.4.3 Total Productive Maintenance (TPM)

It seeks to engage all levels and functions in an organization in maximizing the

overall effectiveness of production equipment. Whereas traditional preventive


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maintenance programs are centered in the maintenance departments, TPM seeks to

involve workers in all departments and levels, from the plant-floor to senior executives,

in ensuring the effective operation of equipment. Autonomous maintenance, a key

aspect of TPM, trains and focuses workers to take care of the equipment and machines

with which they work. TPM addresses the entire production system life cycle and

builds a solid, plant-floor based system to prevent accidents, defects, and breakdowns.

TPM focuses on preventing breakdowns (preventive maintenance), "mistake-proofing"

equipment (or poka-yoke) to prevent breakdowns or to make maintenance easier

(corrective maintenance), designing and installing equipment that needs little or no

maintenance (maintenance prevention), and quickly repairing equipment after

breakdowns occur (breakdown maintenance). TPM's goal is the total elimination of all

losses, including breakdowns, equipment setup and adjustment losses, idling and minor

stoppages, reduced speed, defects and rework, spills and process upset conditions, and

startup and yield losses.

1.4.4 Cellular Manufacturing/One-Piece Flow Systems

In this work units arranged in a sequence that supports a smooth flow of materials and

components through the production process with minimal transport or delay. Rather

than processing multiple parts before sending them on to the next machine or process

step (as is the case in batch-and-queue, or large-lot production), cellular manufacturing

aims to move products through the manufacturing process one-piece at a time, at a rate

determined by customers' needs. Cellular manufacturing can also provide companies

with the flexibility to vary product type or features on the production line in response to

specific customer demands. To make the cellular design work, an organization must

often replace large, high volume production machines with small, flexible, "right-sized"

machines to fit well in the process "cell.". Equipment often must be modified to stop

and signal when a cycle is complete or when problems occur, using a technique called

autonomation (or jidoka). This -transformation often shifts worker responsibilities from

watching a single machine, to managing multiple machines in production cell. While

plant-floorworkers may need to feed or unload pieces at the beginning or end of the

process sequence, they are generally freed to focus on implementing TPM and process

improvements.


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1.4.5 Just-in-time (JIT) Production Systems / Kanban

JIT and cellular manufacturing are closely related, as a

cellular production layout is typically a prerequisite for achieving just-in-time

production. JIT leverages the cellular manufacturing layout to significantly reduce

inventory and work-in-process (WIP). JIT enables a company to produce the products

its customers want, when they want them, in the amount they want. JIT techniques

work to level production, spreading production evenly over time to foster a smoothflow between processes. Varying the mix of products produced on a single line, often

referred to as shish-kebab production, provides an effective means for producing the

desired production mix in a smooth manner. JIT frequently relies on the use of physical

inventory control cues (or kanban) to signal the need to move or produce new raw

materials or components from the previous process. A limited number of reusable

containers are often used as kanban, assuring that only what is needed gets produced.

Many companies implementing lean production systems are also requiring suppliers to

deliver components using JIT. The company signals its suppliers, using computers or

delivery of empty containers, to supply more of a particular component when they are

needed. The end result is typically a significant reduction in waste associated with

unnecessary inventory, WIP, and overproduction

Some of the benefits of JIT are:

It eliminates unnecessary work-in-process, which results in reduction of

inventory costs.

Since units are produced only when they are needed, quality problem

can be detected early.

Since inventory is reduced, the waste of storage space will be

reduced.

Preventing excess production can uncover hidden problems.


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1.4.6 Production Smoothing

In a lean manufacturing system it is important to move to a higher degree of

process control in order to strive to reduce waste. Another tool to accomplish this is

production smoothing. Heijunka, the Japanese word for production smoothing, is where

the manufacturers try to keep the production level as constant as possible from day to

day Heijunka is a concept adapted from the Toyota production system, where in order

to decrease production cost it was necessary to build no more cars and parts than the

number that could be sold. To accomplish this, the production schedule should be

smooth so as to effectively produce the right quantity of parts and efficiently utilize

manpower. If the production level is not constant this leads to waste (such as work-in-

process inventory) at the workplace.

1.4.7 Standardization of Work

A very important principle of waste elimination is the standardization of

worker actions. Standardized work basically ensures that each job is organized and is

carried out in the most effective manner. No mater, who is doing the job, the same level

of quality should be achieved. At Toyota every worker follows the same processing

steps al the time. This includes the time needed to finish a job, the order of steps to

follow for each job, and the parts on hand. By doing this one ensures that line balancing

is achieved, unwarranted work-in-process inventory is minimized and non-value added

activities are reduced. A tool that is used to standardize work is called "takt" time. Takt

(German for rhythm or beat) time refers to how often a part should be produced in a

product family based on the actual customer demand. The target is to produce at a pacenot higher than the takt time (Mid-America Manufacturing Technology Center pres

release, 2000). Takt time is calculated based on the following formula:

Takt Time (TT) Available work time per day = Customer demand per day

1.4.8 Six Sigma


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It is a system and collection of statistical methods for systemically

analyzing processes to reduce process variation, first developed by Motorola in the

1990s. The term sigma is a Greek alphabet letter used to describe variability. A sigma

quality level serves as an indicator of how often defects are likely to occur. A Six

Sigma quality level equates to approximately 3.4 defects per million opportunities,

representing high quality and minimal process variability. Six Sigma's toolbox of

statistical process control and analytical techniques are being used by some

companies who have implemented lean production systems to further drive

productivity and quality improvements. It is important to note that not all companies

using Six Sigma methods are implementing lean manufacturing systems or using

other lean methods. Six Sigma has evolved among some companies to include

methods for implementing and maintaining performance of process improvements.

1.4.9 Other Waste Reduction Techniques

Some of the other waste reductions tools include zero defects, setup reduction,

and line balancing. The goal of zero defects is to ensure that products are fault-free al

the way, through continuous improvement of the manufacturing process. Human

beings almost invariably will make errors. When errors are made and are not caught

then defective parts will appear at the end of the process. However, if the errors can

be prevented before they happen then defective parts can be avoided. One of the tools

that the zero-defect principle uses is poka-yoke. Poka-yoke, which was developed by

Shingo, is an autonomous defect control system that is put on a machine that inspects

al parts to make sure that there are zero defects. The goal of poka-yoke is to observe

the defective parts at the source, detect the cause of the defect, and to avoid moving

the defective part to the next workstation. Ohno at Toyota developed SMED in 1950.

Ohno's idea was to develop a system that could exchange dies in a more speedy way.

By the late 1950's Ohno was able to reduce the time that was required to change dies

from a day to three minutes. The basic idea of SMED is to reduce the set up time on a

machine. There are two types of setups: internal and external. Internal setup activities

are those that can be carried out only while the machine is stopped while external setup

activities are those that can be done while the machine is running. The idea is to move

as many activities as possible from internal to external. After all activities are identified


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then the next step is to try to simplify these activities (e.g., standardize setup, use

fewer bolts). By reducing the setup time many benefits can be realized. First, die-

change specialists are not needed. Inventory can be reduced by producing small batches

and more variety of product mix can be run. Line balancing is considered a greatweapon against waste, especially the wasted time of workers. The idea is to make every

workstation produce the right volume of work that is sent to upstream workstations

without any stop. This will guarantee that each workstation is working in a

synchronized manner, neither faster nor slower than other workstations.

1.4.10 Value Stream Mapping

The Value Stream Mapping method (VSM) is a visualization tool oriented tothe Toyota version of Lean Manufacturing (Toyota Production System). It helps to

understand and streamline work processes using the tools and techniques of Lean

Manufacturing. The goal of VSM is to identify, demonstrate and decrease waste in the

process. Waste being any activity that does not add value to the final product, often

used to demonstrate and decrease the amount of `waste' in a manufacturing system.

VSM can thus serve as a starting point to help management, engineers, production

associates, schedulers, suppliers, and customers recognize waste and identify its causes.

The beauty of value-stream mapping is found in its usefulness and simplicity. VSM

helps answer the question: How do we continuously improve in a capable, sustainable

manner? VSM is a map that outlines the current and future state of a production system,

allowing users to understand where they are and what wasteful acts need to be

eliminated. The user then applies lean manufacturing principals to transition into the

future state.

Thus VSM provides a company with a "blueprint" for strategic planning to deploy the

principles of lean thinking for their transformation into a lean enterprise and it becomes

first step for starting lean thinking. In next chapter we discuss this tool in detail.


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CHAPTER 2

VALUE STREAM

MAPPING


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2.1 HISTORY OF VALUE STREAM MAPPING

The mapping of work processes began with the early industrial engineers from

about 1890 until about 1920. During this period, Frederick Taylor developed

standardized work and time study. Gilberth was the originator of the first process

mapping system originally known as "process charting". Gilberth viewed all work as a

process and developed the symbols and conventions that have most widely used ever

since as described by Lee and Snyder (2006).

In the 1930's and 1940's, Ralph M. Barnes codified the principles and method of

time study and motion economy. During the same period, Allan H. Mogensen

incorporated most of this early work into a system he called "Work Simplification".Work simplification emphasized the use of Gilberth's charting technique and

popularized Gilberth's method.

During the 1950's and 1960's, Toyota realized that to really refine production

methods it was essential to respect the knowledge and expertise of its work force and

use these skills to help develop and refine the end to end process so to produce a vehicle

that the man in street could afford and was reliable too. Shigeo Shingo used these

techniques at Toyota Production System (TPS) began to migrate to the west about 1980

and became known as "Lean Manufacturing after James P. Womack and Daniel T.

Jones wrote their book "The Machine That Changed The World". This led to beginning

of the Lean Manufacturing Era in industries.

In 1990's Mike who had long searched for a means to tie together lean concepts

and techniques, which seemed more disparate than they should be, as he worked on

many plant floor

implementation efforts. He realized mapping had potential far beyond its usage,

formalized the tool, and built training -method around it that has proved extraordinarily

successful. John who worked with Toyota has known about the tool for over 10 years.

Both Mike and John developed the tool and popularized this amazing tool Value Stream

Mapping (VSM) with book "learning to see".

Now days VSM found its uses in offices, hospitals, construction, aerospace

industry, and as environment tool kit.


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Globalization is making most of the organizations, sectors more intensely competitive.

Many organizations are struggling to improve their operating performance in response

to market demands for lower costs, higher-quality products and services, shorter lead

times, and higher returns on investment in infrastructure and resources. The case study

was carried out to address above issues in iron making of an integrated steel plant and

to find out uncover hidden values to increase the productivity. To eliminate the waste

and identify the non value added processes from the lean manufacturing perspective,

the value Stream mapping is carried out to optimize the process and to increase the

productivity.

VSM is the process of visually mapping the flow of information and material as they

are preparing a future state map with better methods and performance. It helps to

visualize the station cycle times, inventory at each stage, manpower and information

flow across the supply chain. VSM enables a company to see the entire process in

both its current and desired future state, which develop the road map that prioritizes the

projects or tasks to bridge the gap between the current state and the future state.

The value stream mapping is used to analyze & map in order to reduce the waste in

processes, enable flow, and to make the process for better efficiency. The purpose of

value stream mapping is to highlight sources of waste and eliminate them by

implementing the future-state value stream that can become a reality. The goal is to

build a chain of production where the individual processes are linked to their

customer(s) either by continuous flow or pull, and each process gets as close as possible

to producing only what its customer(s) need when they need it.

A value stream map is an end-to-end collection of processes/activities that creates value

for the customer. A value stream usually includes people, tools and technologies,

physical facilities, communication channels and policies and procedures. A value

stream is all the actions (both value added and non-value added) currently required to

bring a product through the main flows essential to every product: (a) the production

flow from raw material into the hands of the customer, and (b) the design flow from

concept to launch. Standard terminology, symbols, and improvement methods allows


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VSM to be used as a communication tool for both internal communication and sharing

techniques and results with the larger lean community.

2.2 ACTIVITIES IN VALUE STREAM MAPPING

Before giving the definition of VSM it is important to understand what Value and

Value Stream is. Focus on value in the context of what the customer/end-user is

prepared to pay for. To carry out this activity the company needs to understand what thecustomer requires in terms of features and performance, and how much they are willing

to pay for the product. The outcome of this activity is a clear understanding of what

products the customer requires. These requirements may not be feasible immediately,

but it provides a true representation of customer need.

The

value stream is the entire creation process for a product. The value stream starts at

concept and ends at delivery to the customer. Every stage the product goes through

should add value to the product, but often this is not the case. Mapping of the value

stream aids the identification of value adding and non-value adding (i.e. waste)

activities; some examples are listed below.

Value Adding Activities

Machining, Processing, Painting, Assembling

Non value adding I Waste Activities

Scrapping, Sorting, Storing, Counting, Moving

As per Mike and John (1996) VSM is a "pencil-and-paper tool that helps

users see

and understand the flow of material and information as products make their way

through the value stream".


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The Value Stream Mapping method (VSM) is a visualization tool oriented to

the Toyota version of Lean Manufacturing (Toyota Production System). It helps to

understand and streamline work processes using the tools and techniques of Lean

Manufacturing. The goal of VSM is to identify, demonstrate and decrease waste in the

process. Waste being any activity that does not add value to the final product, often

used to demonstrate and decrease the amount of `waste' in a manufacturing system.

VSM can thus serve as a starting point to help management, engineers, production

associates, schedulers, suppliers, and customers recognize waste and identify its causes.

The value stream includes the value-adding and non value-adding activities that

are required to bring a product from raw material through delivery to the customer. In

other words, VSM is an outline of a products manufacturing life cycle that identifies

each step throughout the production process. Powerful yet simple, no other tool can

outline and distinguish the true value of a product as VSM can. The beauty of value-

stream mapping is found in its usefulness and simplicity. VSM helps answer the

question: How do we continuously improve in a capable, sustainable manner? VSM is a

map that outlines the current and future state of a production system, allowing users to

understand where they are and what wasteful acts need to be eliminated. The user then

applies lean manufacturing principals to transition into the future state.

The current state of the value stream map is drawn to clearly visualize the all

types of waste in value stream, waste throughout the stream must be identified and

eliminated to shorten lead-time and improve the value-added percentage - in other

words, to transform the production system from a batch and push into a one-piece flow

and pull. The only way to identify the waste is to understand the seven elements given

by Hines & Rich (1996) that do not contribute to the value of the product:

overproduction, inventory, transportation, waiting, motion, inappropriate-processing,

and correction (re-work).

All seven elements can be identified (if they exist) on the current-state map. A

list and discussion of these is given as under:

1.Overproduction.2. Waiting.


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3. Transport.

4. Inappropriate processing.

5. Unnecessary inventory.

6. Unnecessary motion.

7. Defects.

1. Overproduction is regarded as the most serious waste as it discourages a

smooth flow of goods or services and is likely to inhibit quality and

productivity. Such overproduction also tends to lead to excessive lead and

storage times. As a result defects may not be detected early, products may

deteriorate and artificial pressures on work rate may be generated. In addition,overproduction leads to excessive work-in-progress stocks which result in the

physical dislocation of operations with consequent poorer communication. This

state of affairs is often encouraged by bonus systems that encourage the push of

unwanted goods. The pull orkanban system was employed by Toyota as away

of overcoming this problem.

2. When time is being used ineffectively, then the Waste ofwaiting occurs. In

factory setting, this waste occur whenever goods were not moving or being

worked on. This waste affects both goods and workers, each spending time

waiting. The ideal state should be no waiting time with a consequent faster flow

of goods. Waiting time for workers may be used for training, maintenance or

kaizen activities and should not result in overproduction.

3. The third waste, Transport, involves goods being moved about. Taken to an

extreme, any movement in the factory could be viewed as waste and so

transport minimization rather than total removal is usually sought. In addition,

double handling and excessive movements are likely to cause damage and

deterioration with the distance of communication between processes

proportional to the time it takes to feed back reports of poor quality and to take

corrective action.

4. Inappropriate processing occurs in situations where overly complex solutions

are found to simple procedures such as using a large inflexible machine instead

of several small flexible ones. The over-complexity generally discourages


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ownership and encourages the employees to overproduce to recover the large

investment in the complex machines. Such an approach encourages poor layout,

leading to excessive transport and poor communication. The ideal, therefore, is

to have the smallest possible machine, capable of producing the required

quality, located next to preceding and subsequent operations. Inappropriate

processing occurs also when machines are used without sufficient safeguards,

such as poke-yoke or jidoka devices, so that poor quality goods are able to be

made.

5. Unnecessary inventory tends to increase lead time, preventing rapid

identification of problems and increasing space, thereby discouraging

communication. Thus, problems are hidden by inventory. To correct these

problems, they first have to be found. This can be achieved only by reducing

inventory. In addition, unnecessary inventories create significant storage costs

and, hence, lower the competitiveness of the organization or value stream

wherein they exist.

6. Unnecessary movements involve the ergonomics of production where

operators have to stretch, bend and pick up when these actions could be

avoided. Such waste is tiring for the employees and is likely to lead to poor

productivity and, often, to quality problems.

7. The bottom-line waste is that ofDefects as these are direct costs. The Toyota

philosophy is that defects should be regarded as opportunities to improve rather

than something to be traded off against what is ultimately poor management.

Thus defects are seized on for immediate kaizen activity.

In summary the principles from the history of lean Manufacturing are to reducewaste (highlight by VSM) through the application of a number of process improvement

tools.

Considerations for Waste Elimination

Value stream mapping is a process designed to reduce lead time, to make product flow,

and to eliminate waste (nonvalue added operations or activities), all for the purpose of


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meeting customer demand at the lowest cost, and with the highest quality. Lean

thinking relies on recognizing the seven wastes over-production, over-processing,

inventory, motion, scrap, waiting, and transportation. Target maps reveal which of these

wastes can be eliminated now, and where. With simulation, it is easy to avoid the

traditional problem of eliminating waste at an operation where there is no net gain. That

is because the revised systems performance can be compared to the current state, to see

the impact of the proposed change.

The key to producing useful target maps is to look for low-cost improvements that

encourage flow, reduce inventory, and test the organizations ability to manage in a lean

environment. The challenge of developing the attitudes, systems and communication

necessary for a true pull system operating at customer takt should not be

underestimated. A high inventory system hides a multitude of problems, which will

slowly be exposed as batch sizes and WIP are reduced. The level of organization and

standardization required for one-piece flow are rarely found in companies with

traditional production planning and traditional management.

1. Over-production

Over-production is the production of material which is not needed now. It usually

occurs in the form of large batches, produced faster than the rate at which they can be

consumed (and ultimately shipped). In job shops, it means working on something

before it can be used by the next step in the process, or before it is required by a

customer. In either case, the result is product that sits in work in process queues, or in afinished goods stock, but is not needed today. Overproduction is caused by a number of

factors, such as long setups, poor quality, machine unreliability, avoidance of setups in

order to make performance measures look better, or the desire to keep an expensive

resource working. Lead time is, of course, directly related to inventory and over-

production. For operations that are easily able to produce at a faster rate than demand, it

is typical that one machine produces a variety of products. This means that the machine

must be changed over periodically. Traditional cost accounting has ways of calculating

the batch size appropriate for a given length of changeover (such as the economic order


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quantity, or EOQ). Changeover time is usually set as a standard, and therefore there is

no argument about how much must be produced each time the machine is set up.

Contrary to Lean thinking, if quality is poor or the machine is subject to breakdowns,

the batch size will be increased. Furthermore, it is not uncommon for operators and

supervisors to decide to produce even more, when things are going well, because well

use it some time, or just in case Lean thinking challenges the notion of a standard

changeover time. Simple industrial engineering will easily point out where changeover

time can be reduced. Good organization and changeover planning, by themselves, are

often capable of reducing setup time by 50%. Standardization and integration of

changeover components will often account for another 25%. This kind of relatively

low-cost improvement will allow setups to take place much more frequently, thus

allowing smaller batches to be run economically. Of course, the kind of machine being

considered here (a stamping press, an injection molding machine, a large mixer, a high

volume printing press, etc.) is shared among a number of product families, so the

impact of change will be felt beyond the product family being considered in the

particular mapping exercise at hand; this may limit which improvement suggestions can

be implemented. Furthermore, if demand is erratic in some product families, it is

unlikely that batch sizes will be reduced by even as much as 50%. It may be necessary

to include demand profiles for these shared products in the target map, in order to test

the feasibility of reducing batch sizes for the product family being considered. With

simulation, try mapping all the value streams that use a particular resource, and add up

operating and setup times for the resource, to see if it can all fit into the available time.

Working ahead is, unfortunately, very common. It is also a significant reason for long

lead times. Working ahead happens for two main reasons. If work lists are available,

operators will tend to put together similar orders, and do them together. This avoids

setup and feeds the natural tendency to gravitate towards repetitive work. Secondly, not

every machine has a full schedule every day, but everyone wants to look busy, so they

tend to overproduce (or slow down). Simple ways to avoid these problems are to put

out only what the next product to be produced is, and to help operators stay busy by

crosstraining them, and then moving them to where the work is when their first task is

complete. In the target map, this is accomplished by putting operators into groups.

When the situation is one of keeping a fast, expensive machine (henceforth called a

super-machine) going, it is easy enough to say that it should only be used whenrequired. However, the reality is that managers and cost accountants want to see it run.


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It takes a real attitude change to admit that super-machines are not always the answer.

Some other potential solutions might be to sell it and buy more appropriate technology

(i.e. smaller, more flexible machines), to shut it down when not needed (and absorb the

overhead elsewhere), or to find more work for it (after solving the setup problem).

Finally, scrap and downtime can be decreased (though not completely eliminated)

relatively cheaply through standardization. Standardization means doing things the

same way each time. Setup is the key here, and standardization of setup means that the

settings and materials are standardized. This leads to less scrap and better reliability,

since each run will have almost identical characteristics to all other runs. Once again,

just being consistent can reduce scrap and increase reliability by about 50%. A lot of

what has been discussed above can be put under the heading of 5S. 5S is an approach to

shop floor cleanliness, organization, and discipline that is considered the foundation of

lean manufacturing. The 5S system consists of five standardized activities,

implemented through five sets of activities:

1. Activity number one (called seiri, or clearing up; popularly Sort) gets rid of all

unnecessary items in the workplace. It creates space and flexibility to do what is

required, without hindrance. The outcome is a standard that states what is allowed in

the workplace, and how often the workplace needs to be reviewed for unused items.

2. The second activity (called seiton or organizing; popularly Separate) finds a

place or role for everything that remains after clearing up. It ensures that everyone

knows where to find what they need with a minimum of delay.

The outcome is a standard that states where everything is to be found at all times, and

systems for laying out work areas so that the most frequently used items are closest at

hand.

3. The third activity (called seiso or cleaning; popularly, Shine) ensures that

everything works well and is properly adjusted, through operators checking and

cleaning the workplace regularly. The resulting standard specifies how often the


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cleaning and checking activity should take place, and includes it in the scheduling of

work (much like breaks and meetings are scheduled).

The fourth and fifth aspects of the 5S system are not so much transformative steps as

they are activities designed to maintain the state of affairs created through the first three

steps.

4. The fourth step (called seiketsu or standardizing; popularly Standardize) makes

sure that as the right way of doing things is discovered, it is turned into a standard

practice, through development of policies and procedures.The standard forstandardizing spells out review periods, and the data to be collected to ensure that the

policies and procedures are working as expected.

5. Finally, the fifth step (called shitsuke or training and discipline; popularly

Sustain) gets to the personal level, and demands that each member of the group is

aware of what the rules are, and follows them. Without this level of standardized

behavior, the 5S system will not be effective. Standardizing this aspect means ensuring

that there is continuous improvement in what each person knows and is able to do, and

in adherence to ever more stringent standards.

2. Over-processing

There are two aspects to this kind of waste (1) overdoing it in the sense of doing too

much, too soon, and beyond what is necessary; and (2) using inappropriate equipment,

especially equipment that is much larger, faster, or more complicated than necessary. It

can be difficult to distinguish between over-processing and over-production, because

the first often leads to the second. Over-processing is usually associated with going

beyond what the customer requires. Examples are reports and presentations that have

more information than the audience is looking for, and therefore are difficult to

understand and act on. Products may be designed with more features than the customerneeds, which end up being difficult to learn to use, and which cost more than necessary.


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In the rush to outdo its competition, a company may offer far more features than the

market demands. In doing so, they add unnecessary complexity to the layout, process,

and product, and subsequently suffer from poor quality, longer lead times and higher

costs.

Over-processing, in the second sense, can also be associated with super-machines.

These are machines built for mass-production, and are capable of production rates far

exceeding customer requirements. Many problems are associated with these production

centers. They tend to be difficult to repair, and since most factories only have one, they

can actually cause shortages when they are out of commission. It can be difficult to

determine the source of quality problems, due to their complexity. It is very difficult to

incorporate them into schedules, since they usually have long setups. In other words,

they rob a plant of flexibility. When starting the journey to Lean, the first action should

be to get rid of super-machines, and replace them with appropriately sized machines

(usually several of them) that can be dedicated to individual product families.

Since super-machines are usually only replaced at long intervals, using appropriately

sized machines will also ensure that upto- date technology is constantly flowing into the

factory, as the smaller machines will be replaced more frequently.

The final reason for over-processing has to do with excessive processing in the form of

removal of material, or requiring several assembly steps, when a near net shape piece

of material would have required less. Examples include using two steps to assemble a

metal part to a plastic part, when insert molding could have accomplished this in onestep; operators trimming flash from plastic parts, when a well-maintained mould could

eliminate this operation altogether; or having a cutting department, when steel could be

purchased already cut to size.

3. Inventory


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Whether in the form of work in process (WIP) or finished goods, inventory is

considered the great evil of production. With material always available, the focus is

taken away from the process, quality, and the rate of work. Inventory thus actually

hides problems that exist in the production system. Over-production leads to waste

associated with inventory, in requiring extra space for storage, time and effort spent

controlling inventory, money tied up in purchased materials, the potential for damage

and obsolescence rendering the inventory unfit for use, the need for larger material

handling systems to move larger quantities of goods, and increase in lead time for

delivery, to name only a few direct costs! In addition, inventory has an impact on waste

that is indirectly caused by having more than needed. Inventory leads to a lack of

attention to the process. This means that processes are designed with cycle times well

outside of the average. By buffering the process with inventory, the wide variance in

cycle times is not noticed until an attempt is made to set up a continuous flow cell or

line. Equipment must then be replaced, or great effort expended trying to balance the

flow to the rate of customer pull. The reliability of the machine can also be overlooked

when there is plenty of inventory. In a system with reduced inventory, reliability must

be very high, or everything comes to a quick halt. Lean factories achieve 100% uptime

through 5S, productive maintenance, and simple machines. The same holds for quality.

While mistakes will be made (as Shingo noted in Zero Defects), control must be 100%

at the source. In getting to 100% defect-free production, rapid problem solving (at the

machine) is a must; quick development of mistake-proofing devices and the use of

simple, capable machines is also a must. Finally, standardization of work is necessary

to achieving smooth flow and reducing inventory to a minimum. All activities should

have a standard time, and all personnel must know and follow the standard procedure.

This goes for assembly, loading and unloading, changeover, machine operation, and

other activities.

4. Transportation

When a facility layout extends over a large area, the movement of inventory from

operation to operation becomes necessary. It is thus another result of over-production. It

also results from laying out production equipment by function. Functional layout places

each type of machine (stamping presses, welders, injection molding machines, etc.) in


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its own department, for a variety of reasons, mainly to do with the perceived benefits

of specialization. The result, however, is usually over-production. When looked at from

the point of view of uninterrupted flow of production, a functional layout is counter-

productive. Focused factories, and cellular layouts, keep the equipment required for

producing a family of products together. This is done in order to balance flow from one

operation to the next, to provide rapid feedback on quality from one operation to the

previous, to balance the number of operators to production requirements, and to allow

pride in customer service. Creating a focused factory (a small space devoted to a

product family, with all the necessary equipment for producing the products of the

family), or setting up a cell (a group of machines which have one or at most a few

pieces of WIP between operations, and usually laid out in a U-shape) brings the issue of

over-processing to the fore, since in most circumstances the various pieces of

equipment are not matched in production rate. It does, however, solve the issue of

wasteful transportation, since the operations are now in close proximity. Movement of

material can be accomplished using small containers, small hand-carts, gravity flow

conveyors, or even taking a step or two from one operation to the next operation with

the workpiece. Additional benefits of eliminating large material handling machinery

include less damage to facility and WIP, the option of using narrower aisles, improved

safety, and lower costs. In a cell or focused factory, visual control is much easier as

well.

5. Motion

Motion is a waste associated with both operators and equipment. In the case of

operators, wasted motion includes bending, walking to get or place parts, lifting, and

taking more than one step to reach or view machine interfaces. In setups, it includes

moving around the machine repeatedly to carry out the steps in the changeover in an

unplanned fashion. Motion can add significantly to cycle time, and must therefore be

considered separately when creating and balancing cells and focused factories. The

waste of motion is reduced through ergonomics, work planning, standardization of

work, 5S, and using smaller containers. In the case of equipment, wasted motion is

associated with long strokes, air cut, and other non-production movement of machine

parts. In designing machines, the emphasis is often on versatility. This is associated


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with functional layouts and batch production. A general purpose machine is designed to

handle a variety of tools. But from the point of view of continuous flow, this is not

necessary, and waste therefore results. The solution is to customize the machine to its

purpose, which is most easily accomplished when the machine is simple to start with.

6. Scrap

Scrap and rework are obviously wasteful. In batch production, scrap is rarely visible,

since there is always more material available, and the run can be extended for a short

while to produce the required quantity. In a continuous flow system, scrap is a seriousproblem, since every machine loses a cycle when a piece is rejected. This destroys

balance, and when producing to customer takt, results in a missed shipment. When

perfect quality is required, 100% source inspection is necessary. This is achieved

through mistake proofing (poka-yoke), as Shingo has so elegantly shown. It also, of

course, rests on good maintenance, equipment improvement to achieve greater

reliability, and simplification of production machinery. 5S (especially cleaning and

checking) and standardization of work are also significant in reducing mistakes and

defects. Design for manufacturability and simplification of processing can also help

considerably to reduce scrap and rework. It should be noted that rework is as serious a

problem as scrap, since, from the point of view of time, both are lost cycles.

7. Waiting

Waiting takes a number of forms. Operators wait for machines to complete their cycle,

or for material to arrive so they can work on it. Machines wait for work, and also for

operators to load and unload work pieces or other production material. The kinds of

waiting that are common in batch production facilities are different from the waiting

that is wasteful in a continuous flow system. Most batch systems strive to keep

equipment working at all times. This requires buffers of inventory to be placed in front

of all machines. By assigning operators to specific machines, they are consequently

kept busy.


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In the progress to single piece flow, keeping all machines busy is not a goal (equipment

is a sunk cost). The goal is to produce what is required by the customer, and no more. If

a machine is capable of doing more, it is considered the wrong machine for the job.

Over-production results from keeping the machine operating. It is considered important,

however, to keep operators busy at all times. This is accomplished by moving operators

from operation to operation, as the work flows through the process. This starts by

completing the needed work (for example one days or weeks worth) at one station,

and then moving on to the next step. With better balancing and training, as well as

reduced setup time and improved reliability, it is possible to construct cells, where the

number of operators is balanced with the required work, and there is only a small

amount of work in front of each machine (an hours worth, or even only a single piece).

Spare time should be used for continuous improvement activities and extra 5S

operations.

2.3 VALUE STREAM MAPPING OBJECTIVES

Various objectives of using VSM as given by Mike and John (1996) are listed

below:

1. It helps to visualize more than just the single- process level, i.e. assembly,

welding, etc., in production. One can see the flow.

2. It helps to see more than the waste. Mapping helps to see the sources of waste in

your value stream.3. It provides a common language for talking about manufacturing process.

4. It makes decisions about the flow apparent, so one can discuss them. Otherwise,

many details and decisions on the shop floor just happen by default.

5. It ties together lean concepts and techniques, which helps to avoid "cherry

picking".

6. It shows the linkage between the information flow and the material flow. No

other tool does this.


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7. Provides a company with a "blueprint" for strategic planning to deploy the

principles of Lean Thinking for their transformation into a Lean Enterprise.

2 .4 H OW TO U SE VA LU E S TR EA M M AP PI NG

Mapping the value stream is a big-picture technique that takes into

consideration all processes and seeks to improve the enterprise as a- whole. In essence,

the map is a simplified visual blueprint that identifies value and waste throughout the

system and encourages a systematic approach to eliminating waste. The overall goal of

VSM is to move from batch and push to one-piece flow and pull through the entire

value stream. The ultimate goal is to design and introduce a lean value stream that

optimizes the f low of the entire system - from information, to material, to finished

goods arriving at the customer's door. Lead-time, inventory, and over-production are

therefore reduced; throughput, efficiency, and quality are improved.

Using a VSM process requires development of maps: a Current State Map and a

Future State Map. In the Current State Map, one would normally start by mapping a

large-quantity and high-revenue product family. The material f low (left to right) will

then be mapped using appropriate icons in the rich VSM icon template. The product

will be tracked from the final operation in its routing to the raw material storage.

Relevant data for each operation, such as the current schedule (push, pull, order

dispatching rules ) and the amount of inventory in queue, will be recorded. The

information f low (right to left) is also incorporated to provide demand information,

which is an essential parameter for determining the "pacemaker" process in the

production system. After both material and information flows have been mapped, a

time-line is displayed at the bottom of the map showing the processing time for each

operation and the transfer delays between operations.

The time-line is used to identify the value-adding steps, as well as wastes, in the

current system. The comparison between the processing times and the takt time

(calculated as Available Capacity/Customer Demand) is a preliminary measure of the

value and waste. This takt time is mostly used as an ideal time for each operation to

achieve (ideally, the cycle time for each operation should be the takt time).


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Based on the analysis of the Current State Map, one then develops a Future

State Map by improving the value-adding steps and eliminating the non-value adding

steps (waste)

2.5 VARIOUS APPLICATIONS OF VALUE STREAM MAPPING

Now days, VSM is applicable in different fields other then automobile manufacturing.

These are illustrated below:

1. VSM is uses in Administrative and Office Processes, the translation of lean

factory principles into the office as given by Keyte and Locher (2004)

2. This tool was applied to redesign the department's core engineering design

process by Goubergen and Landeghem.

3. Value Stream Analysis and Mapping (VSA/M) is uses by McManus and Millard

(2002) as tool to improve Product Development (PD) business process.

4. VSM is used in medical clinics to design, implement, and maintain an

integrated information system with two other health-care entities as per Snyder,

Paulson and McGrath. (2005)

5. VSM is used for the development of a supplier network around a prominent

distributor of electronic, electrical and mechanical components by Hines, Rich

and Esain (1997)

6. VSM can provide necessary information for analysis of equipment replacement

decision problems as per Sullivan et al (2002)

2.6 OBJECTIVE OF RESEARCH

Today, automotive suppliers have a great concern over improving quality and

delivery and decreasing cost, which leads to improved system productivity. In order to

remain competitive, waste from the value stream must be identified and eliminated so

to run system with maximum efficiencies.

A Production is to order and large numbers of different products are produced,

each in relatively small volume. A Production shop consists of number of machine

centres, each with a fundamentally different activity. The problems of machine shop are

delayed deliveries, long queues, and high work in process inventories, improper


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utilization. These problems increase overall cost of production. The need for

customized products/parts with reduced lead times together with the requirement of

global competitiveness requires that products/parts be produced in small batch sizes as

per customer's requirement. The processing in small batch sizes necessitates theadjustment in the flow of production through different processes as per their processing

speeds. In addition it requires close monitoring of processes to reduce process

variability (defect free production), efficient planned maintenance of all machines (for

increased availability) and reduction in non value added activities such as setup times,

movement of material in between the work processes and additional processing of

material. The efficient utilization of machines while producing in small batches reduced

WIP inventories, reduced throughput times and reduction in lead times leads to

competitive manufacturing. It is need for machine shop manufacturing system to adopt

lean environment.

To improve productivity by identifying waste and then removing that by

implementing lean principle in this industry we focus our attention on VSM tool. Value

Stream Mapping enables a company to identify and eliminate waste, thereby

streamlining work processes, cutting lead times, reducing costs and increasing quality

and hence productivity. The goal of VSM is to identify, demonstrate and decrease wastein the process, highlighting the opportunities for improvement that will most

significantly impact the overall production system. In this study lean concepts are

introduced using VSM in working environment. Methodology for drawing VSM in

industry is discussed in detail in next chapter.


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Literature review related to concept of Lean Manufacturing:

Haycs and Clark (1986) established that transportation time is another source of

waste. Moving parts from one end of the facility to another end does not add value to

the product. Thus, it is important to decrease transportation times within the

manufacturing process. One way to do this is to utilize a cellular manufacturing layoutto ensure a continuous flow of the product. This also helps eliminate one other source

of waste, which is energy. When machines and people are grouped into-cells

unproductive operations 'can be minimized because a group of people can be fully

dedicated to that cell and this avoids excess human utilization. Another source of waste

is defects and scrap materials. Manufacturing parts that are fault-free from the

beginning have profound consequences for productivity.

Drucker (1987) discussed the problems of existing union work rules and job

classifications in the implementation of J11- systems. It is often assumed that because

implementation of most manufacturing practices requires negotiating changes in work

organization, unionized facilities will resist adopting lean practices and thus lag behind

non-unionized facilities. The business press has often asserted that unionization

prevents the adoption of some "Japanese" manufacturing practices in US manufacturers

Ohno (1988) identified that the Toyota production system has been created on

the practice and evolution of one very useful technique that reduces cost and time while

challenges every activity in the value stream. It is applying a methodology known as the

"Five whys, "By asking why an activity is performed and then asking why after each

response, it is frequently possible to get to the origin of the problem. Understanding the

root cause assists in successful redesign.

Womack et al (1990) explained the several features of lean, According to studies

that were initially performed in the automobile industry.


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(1) Lean is a dynamic process of change driven by a systematic set of principles

and best practices aimed at continuously improving;

(2) Lean refers to the total enterprise, from the shop floor to the executive suite, and

from the supplier to customer value chain;

(3) Lean requires rooting out everything that is non-value-added; and

(4) Becoming lean is a complex business - there is no single thing that will make an

organization lean.

Turnbull et al (1992) documented the adoption of the Japanese model of

manufacturing in the UK automobile industries. It is argued that the Japanese model

involves very high intra and intergenerational dependences. Although this does not causeproblems in Japan due to the structure of the Japanese motor industry, the structure of the

UK vehicle industry present severe obstacles in the successful use of Japanese systems.

Such exercises may even sweep away potential strengths of the existing supplier.

Braiden and Morrison (1996) utilized lean manufacturing to identify

bottlenecks in automotive motor compartment system. As a result greater production

capacity was created by increasing the up time to over 90%. The current manufacturing

system optimization carried out through lean initiatives.

Cooper (1996)emphasized that lean thinking is related with quality and value

for each product from the perspective of the end-customer. Lean producers rely on

confrontational strategies to compete head-on for market share by developing competitive

advantages. To successfully engage in confrontation, a firm must become expert at

developing low-cost, high-quality products that have the functionality customers demand.

Dankbaar (1997) established that lean production makes optimal use of the

skills of the workforce, by giving workers more than one task, by integrating direct and

indirect work, and by encouraging continuous improvement activities. As a result, lean

production is able to manufacture a larger variety of products, at lower costs and higher

quality, with less of every input, compared to traditional mass production: less human

effort, less space, less investment, and less development time.

Liker (1997) reported that the benefits of lean manufacturing generally are

lower costs, higher quality, and shorter lead times. The term lean manufacturing is

created to represent less human effort in the company, less manufacturing space, less


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investment in tools, less inventory in progress, and less engineering hours to develop a

new product in less time. Shingo (1997) developed the concept of single minute

exchange of dies (SMED) to reduce set up times; for instance, setup times in large

punch presses could be reduced from hours to less than ten minutes. This has a bigeffect on reducing lot sizes. Another way to reduce inventory is by trying to minimize

machine downtime. This can be done by preventive maintenance. It is clear that when

inventory is reduced other sources of waste are reduced too. For example, space that

was used to keep inventory can be utilized for other things such as to increase facility

capacity. Also, reduction in setup times as a means to reduce inventory simultaneously

saves time, thus reduces time as a source of waste

Hines et al (1998) found an application of value stream mapping in the

distribution industry. Partsco, a distributor of electronic, electrical, and mechanical

component decided to map the activities between the firm and its suppliers. Partsco

introduce EDI which allowed the firm to work with its suppliers effectively and more

quickly. In a short time period the company was able to reduce the lead-time from 8 to

7 days.

Burr and Liker (1999) used advanced planning and scheduling (APS) for shop

floor production as an enabler of lean manufacturing. The forerunner to modem APS

like MRP and finite forward scheduling packages were used to schedule "push system"

and generate schedule down to the level

Intro and Lit Rew

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