report on just in time and lean manufacuring
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CHAPTER 1 INTRODUCTION
Just in time (JIT) is a management philosophy that strives to eliminate sources of
manufacturing waste by producing the right part in the right place at the right time. Waste
results from any activity, which adds cost without adding value, such as moving and storing.
JIT (also known as stockless production) should improve profits and return on investment by
reducing inventory levels (increasing the inventory turnover rate), improving product quality,
reducing production and delivery lead times, and reducing other costs (such as those
associated with machine setup and equipment breakdown).
The idea of producing the necessary units in the necessary quantities at the necessary
time is described by the short term Just-in-time. Just-in-time means, for example, that in the
process of assembling the parts to build a car, the necessary kind of sub-assemblies of the
preceding processes should arrive at the product line at the time needed in the necessary
quantities. If Just-in-time is realized in the entire firm, then unnecessary inventories in the
factory will be completely eliminated, making stores or warehouses unnecessary. The
inventory carrying costs will be diminished, and the ratio of capital turnover will be increased.
The implementation of this management philosophy in industries like the automobile
industry can bring about a see saw change in both quality & quantity since in a JIT system,
underutilized (excess) capacity is used instead of buffer inventories to hedge against problems
that may arise. JIT applies primarily to repetitive manufacturing processes in which the same
products and components are produced over and over again. The general idea is to establish
flow processes (even when the facility uses a jobbing or batch process layout) by linking work
centers so that there is an even, balanced flow of materials throughout the entire production
process, similar to that found in an assembly line. To accomplish this, an attempt is made to
reach the goals of driving all queues toward zero and achieving the ideal lot size of one unit.
This new trend in engineering production, which originally refers to the production of
goods to meet customer demand exactly, in time, quality and quantity, reduces wastage by
nearly 55-75%. "Waste" in this context is taken in its most general sense and includes time
and resources as well as goods. This concept can really change the phase of industrial
production of goods like car & other important utilities.
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Lean Manufacturing can be defined as a systematic approach to identifying and eliminating
waste (non-value-added activities) through continuous improvement by flowing the product at
the pull of the customer in pursuit of perfection.
The term lean manufacturing is a more generic term and refers to the general
principles and further developments of becoming lean.
The term lean is very apt because in lean manufacturing the emphasis is on cutting out
FAT or wastes in manufacturing process. Waste is defined as anything that does not add
any value to the product. It could be defined as anything the customer is not willing to pay
for.
Manufacturing philosophy is pivoted on designing a manufacturing system that
perfectly blends together the fundamentals of minimizing costs and maximizing profit. These
fundamentals are Man (labour), Materials and Machines (equipments) called the 3 Ms of
manufacturing. A well-balanced 3M is resulted through lean manufacturing.
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CHAPTER 2 HISTORY
It is a popular fact that JIT system started in the initial years after the World War II in
Japan for the Toyota automobile system. Toyoda family in Japan decided to change their
automatic loom manufacturing business to the automobile business. But they had few
problems to overcome. They could not compete with the giants like Ford in the foreign
markets. Therefore Toyota had to depend upon the small local markets. They also had to bring
down the raw materials from outside. Also they had to produce in smallbatches. They havent
had much of capital to work with. Therefore capital was very important. With these constrains
Taiichi Ohno took over the challenge of achieving the impossible. With his right hand man
Dr. Sheigo Shingo for next three decades he built the Toyota production system or the Just In
Time system.
Although the concept was mastered in Japan for the Toyota production system, the
roots of this concept goes into the sixteenth century. Eli Whitneys concept of interchangeable
parts said to be the very initial beginning of this concept. But first or at least famous
implementation of something similar to JIT happened a century later in manufacturing of Ford
Model T (in 1910) automobile design. Manufacturing was based on line assembly. Every part
moved without interruptions to the next value adding point. Parts are manufactured and
assembled in a continuous flow. Even Henry Ford may not have understood the basics behind
his system. But it saved lots of money and made Henry Ford a richest on the planet at that
( Figure: 2.1 )
( Taiichi Ohno )
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time. Although very successful in the initial years, Ford system had it drawbacks. One of the
major drawbacks was that its inability to the change. This was due to the push strategy
implemented in the Fords system. They relied on keeping machine busy without thinking
about the final outcome. They had huge stocks in the form of finished goods and in the form
of Work In Progress. This led to the inflexibility of the system. Also this wasted money
unnoticed. Another major drawback of the system was the poor handling of the human
resource. This led to have a less motivated set of people in the organization.
But in Japan, they studied the system very well and saw the problems that Ford system
had. But the core concept of the Ford system was obeyed. This is the continuous flow of value
system. Anything distracting it treated as a waste. Various pioneered work from people like
Deming and Juran in the field of quality improvement was used in the system. This bought
built in quality to the system. More importantly Ohno and Shingo understood the drawbacks
in the push system and understood the role played by the inventory. This led to Pull system
rather than the push system, where the parts are produced only when they are pulled by the
process before that. This is similar to the concepts in the super markets. When the shells are
being emptied (that is when people buy the product), they are refilled with new ones.
This system developed in Toyota from 1949 to 1975 virtually unnoticed by the others even
within Japan. But in the oil crisis in 1973 Japan economy suffered and most of the industries
had losses. But Toyota overcame these problems. They stood out from the rest. This was the
eye opener for other Japanese firms to implement this system. But this system got popular in
the western world with the book The machine that change the world written by James
Womack in 1990. This book was aimed to give the history of the automobile with the plant
details of some of these manufacturers. He gave the name Lean Manufacturing to this
system. This was the eye opener for the western world about this system. Thereafter the
concepts were practiced all over the world. Experiences and knowledge vastly improved the
system.
But there were many people who just tried to use the tools in lean manufacturing
without understanding the meaning of them. They eventually failed. But there are number of
places this system is working well. The complete elimination waste is the target of the system.
This concept is vitally important today since in todays highly competitive world there is
nothing we can waste.
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CHAPTER 3 MANUFACTURING WASTE
Waste is defined as anything that does not add value to the final product. The wastes
are everywhere in many different forms. Every organization wastes majority of their
resources. Therefore it is worthier to have a closer look at these wastes. For the ease of
understanding these and due to many other similarities, these wastes are categorized in to
seven categories. In some instances one extra category is added to make the total of eight
waste categories. Since I feel this eighth category is very important I will go by this
categorization. Every waste you will come across in your organization or even in day-to-day
life will fall into one of these categories. Following are these waste categories.
Over production Waiting Work In Progress (WIP) Transportation Inappropriate processing Excess motion or ergonomic problems Defected products Underutilization of employees
Although in deferent groups, each one of these is interconnected. Therefore one change will
affect the total system. You will see later in this chapter how closely these are interconnected
to make the mesh of wastes in every organization.
3.1. Over Production
The word over production can be used to describe a type of waste which is in most of
the places and we never think this as a waste. This is producing something before it is actually
required. This can be applied to the bigger picture or in more localized sense.
In the bigger picture, this is equivalent to create a product or a service before it is
actually required. Lean manufacturing always trust on the pulling rather than pushing. This
means that every product or a service must be pulled from the process immediately after that.
Therefore a product or a service must be pulled by the customer. In much more simpler way,
customer must have the real requirement for the product or the service being produced. If you
produce the goods without any stimulation from the market, then either you will have to keep
the product with you until there is a market for that product or you have to create the market
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stimulation with huge advertising campaigns etc. this is known as the push strategy. Still you
will not have the guaranty that this will be able to sell the products without wastages.
In the much smaller picture, the word over production might mean producing a part of
a product before it is required by the assembly line or the process after that. For an example
there is no point of making more receivers than the phones intended to be produced. The extra
amount will be a lost.
Over production accounts for many loses. One is the waste due to unnecessary parts.
This also will make the WIP higher. Flow will not be smoother. This obviously leads to low
quality products and defects as quality problems are hidden in the WIP maintained due to over
production.
3.2. Waiting
In conventional batch processing, some studies show that 90% of the time goods are
waiting to be processed. Some even say this is higher as 99%. Even a single minute lost in
waiting cannot be recovered in the process there after. Think carefully. Analyze how long the
products are waiting against the time used for processing them. I am sure you will be shocked.
This is one big contributory factor for the higher lead times. This simply means you take 100
hours or more to complete work which is worthier only 10 hours. Ninety hours or more is lost
and added to the lead time. No waiting means you can deliver the goods within 10 days which
actually took 100 days earlier. Think about the flexibility you will get with this. If you can do
this, you are there to compete with the changing markets and react to the changes very fast,
even before your competitors think about it. This will also reduce the WIP and tons of related
problems. Also considerable savings on the production space and reduction in work in capital
can be achieved. Among the cause of this problem is due to the high volume machinery,
unawareness of the people, and conventional thinking of the people play leading roles.
3.3. Work In Progress
Work in progress or WIP is a direct result of over production and waiting. Every
imperfection in the system will create a requirement for the WIP. Therefore WIP also known
as the mirror of the wastes that system has. But WIP itself becomes a waste due to many
consequences. It blocks money in the form of not finished products. It also reduces the
flexibility of the production facility by increasing the change over time between different
styles. It hides quality damages, and will only be revealed when a considerable damage is
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done. Higher WIP also requires larger floor space. This will also affect the appearance of the
work place badly. Therefore if you want to be perfect, just target for a system where there is
no requirement for WIP.
3.4. Transportation
No matter how well you do transporting. It does not add value to the end product.
Therefore simply transportation is one of the wastes that have to be eliminated from the
production system. This accounts for the quality defects, maintenance of a higher WIP, and
additional cost of transporting the goods. Transportation often caused by poor work place
organization.
Inflexibility of the layout plays a big role here. This can be avoided with careful re
designing of the layouts.
3.5. Inappropriate processing
This is the using incorrect tools for the job. This does not mean that you should use
complicated or expensive tools to do the job. It is about using the correct tool for the correct
job. Low cost automation is one program where Toyota found to be really effective.
Developing such tools can be done with the aid of workers, because they know the job they
do more than anyone. Then this will become a very good way of motivating people as well.
The enemy for this system is the mindset of the people who work in the organization. People
naturally think like best equipment for the job is expensive and complex. So how to overcome
this problem, which will not only save money for you but also motivate people immensely.
Very simple. Change the mindset of the people by education and training. Also create a
culture of continuous improvement. Then people will always look for the better ways of doing
things, which creates opportunity for these kinds of innovations.
3.6. Excess motions
This waste is often overlooked. When performing a certain task people have to repeat
their motions again and again. Although we do not realize, in many places people will have to
move, bend or reach to collect some part or to reach a machine. If a time study can be done to
check the percentage of the time for these unnecessary movements, you will see it is actually
very high than you think. Even the other ergonomic conditions like correct lighting, tool
arrangement, work process management is essential to achieve a good productivity from the
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people poor conditions are not good for the health of the worker obviously. Also this will
waste large amounts of time. Workplaces will become very untidy. Workers will get tired
easily. The reason for this is poor workplace organization. To overcome this problem, a
detailed study has to be carried out about working conditions. Then they have to be re
arranged to eliminate these problems. Even some simple equipment change like from normal
chairs to movable and adjustable chairs will solve some problems. But some problems will
need very good workplace engineering to overcome.
3.7. Defected products
The entire above are wastes themselves. But they lead to another waste which is
extremely costly. These are the defected product. In the case of services this is the poorquality of the service. Defects call for higher inspection and related costs. If you find a defect,
you will have to remove it. The raw materials, time, effort and the money put in to this
product will be wasted. Even worst, if this defected product goes to the customers hand you
will lose the image for your organization. Also there is a risk of claims. In the long run this
will be a big cost for the organization. Damage in a single dollar product can create millions
of dollars of lost to your organization. As I mentioned earlier all the above wastes, poor raw
material, mistakes from the workers, problems in the system, machinery problems and much
more accounts for this problem. So removing this from the system is long time task. Making
the system fool proofed, getting good quality raw material, educating people are among the
solutions for this.
3.8. Underutilization of human resource
As I mentioned earlier in the chapter, the eighth waste for me the largest of the all. But
most people do not think this as a waste. Think about Japan. They are not a nation blessedwith natural resources as other countries. But they are in the top of the world today. How they
managed to do this. Simply by using their human resource to its full potential.
Every worker, even the people do the most routine job in the organization will have
something to contribute to the organization than their muscle power. Think about a floor
cleaner. If you ask him, how to clean the floor much faster, I am sure they will come up with
some fantastic ideas.
What lean manufacturing tries to do is to get ideas from all level of the people in the
organization and to use them for the betterment of the organization. Therefore not making the
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full use of the human resource is a waste. Wasting this without using to fight against the
wastes is the biggest loss for the organization.
Most of the times the human talents are deteriorated because they are not identified by
the decision makers. Decision makers do not have the mind set of managing human resource
productively. Also most of the organizations do not have a proper system to use the talents of
the people. They also do not have a good motivation and rewarding system for the talents. If
people are not being rewarded, they will not come out with their full potential.
Overcoming this problem is a very long termed task. But even some simple techniques
can give you good results. You can simply keep a suggestion box and ask people to put their
ideas into it to regarding the productivity improvement. Motivate them with some cash or
with recognition. See the results. You will have a potential of saving lot of money. More than
that people will get motivated and will have a chain effect. Human brains and hearts are
valuable even than the most expensive machinery in the world.
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CHAPTER 4 LEAN MANUFACTURING TOOL
Lean manufacturing is based on continuous finding and removal of the wastes. Value
is defined from the customers point of view. Therefore all the tools in lean manufacturing aim
to identify and remove wastes from the system continuously. There are four steps in
implementing lean manufacturing. They are;
1. Identifying the fact that there are wastes to be removed
2. Analyzing the wastes and finding the root causes for these wastes
3. Finding the solution for these root causes
4. Application of these solutions and achieving the objective
When this is done go back to the stage 1 and continue this loop over and over again.
To become lean it is very necessary to understand the fact that wastes are there. You
must also be able to find out where these wastes do exist. Then you will be able to find out the
root causes for these problems and then come up with a way to solve it. To find out where in
the process these wastes exist there is a very powerful and simple tool. This well known tool
is process mapping.
Process map simply maps all the processes and the activities which are carried out in
bringing a specific product or a service in to a reality. Irrelevant of the value they add to the
final product or the service, the process map includes all the activities from the point of
development or order inquiry to making and shipping the goods and up to the point where
customer collects the goods.
By sticking to a single product or a service you will find it very easy to make the
process map. This also makes it easy to understand the process when someone refers to the
process map. Or another way you can create a map which is simpler and easy to understand is
by creating a overall map with all the departments and their interconnectivity, and then map
the processes within the departments separately. This way you will get a good map which is
simpler to understand and much more conclusive. You can use the standard symbols used in
the process mapping to create a process map which can be understand by all the people easily.
When you map the process, you will start to see the;
1. Value added and
2. Non value added activities
You will also have better idea of what are the avoidable, non value added activities
and what are the non values added unavoidable activities.
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After understanding these clearly, you have to create the process map for the future.
This will include only the value added activities and the non value added but unavoidable
activities. The process changes and the lay out changes etc are also possible in creating this
ideal layout. This is so important since there after your aim is to get this ideal position. This
will be the aim for your future.
By now you have clearly understand the wastes that you have to remove from the
system. But what should be given the priority. Finding the order of the problems that should
be according to the priority of talking is one of the very important issues to be addressed
correctly.
One tool which is very important in this is the Pareto Analysis or the Pareto
Curve. This will give you the importance of each problem to the system. Then you will be
able to tackle the problems easily according to their importance. Refer to the chat below.
After finding out the order of talking of the problems, you have to find out the root
causes for these problems in order to avoid these problems. For an example if you have
frequent machine breakdowns, you will find the cause for this problem is untrained workers,
poor maintenance, poor quality machinery used etc. then you will be able to analyze these
causes again find out the causes for them as well. For an example why the staff is not trained
( Figure: 4.1 )
Pareto Curve
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properly is because most of them are new and have not had enough time to be trained. Then
you will be able to come up with a way of training people when they just join in so that you
will avoid this problem. It is generally advised that not to go than three steps down the line in
finding root causes.
One tool which is extremely important in understanding the root causes of the
problems is brain storming. Also various data collection techniques and analyzing techniques
will help in finding out these root causes. Representing these root causes and their relevance
to the immediate problem can be achieved with a cause effect diagram or a Ishikawa
Diagram.
Lean manufacturing offers few readymade and well proven solutions for any industry.
But always you have to customize these solutions to suit your organization. Always keep in
mind, lean manufacturing does not start with the tools, it starts with lean thinking. Now here
below discuss lean manufacturing tool in details.
4.1. JIT (Just In Time)
Often this term JIT is used with JIT interchangeably. It is that much interconnected
with lean manufacturing; in fact JIT is the backbone of the lean manufacturing. Actually the
concept grew first with the Toyota system was the JIT. Then it developed to the lean
manufacturing.
( Figure: 4.2 )
( Ishikawa Diagram )
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JIT is one key way to get read of most of the wastes which we have already discussed
in the early chapters. JIT concepts are based on the pull demand model. Everything is done
when they are actually needed. JIT has three main areas.
JIT Purchasing
JIT Production
JIT Distribution
4.1.1. JIT Purchasing
Purchasing is done when the goods are actually needed by the production. No large
stocks are maintained. Often purchasing is done in small batches continuously. This allow
production to run smoothly. This will also reduce the costs due to storage, and also will
minimize the degrading of the goods. This way it is easy to monitor quality defects and
correct them if there are any in the subsequent batches. Also this will help to achieve shorter
lead-times in the production.
But achieving this has problems to overcome. First of all the supplier base of the
organization should be manageable. Then they have to agree to produce in small batches and
send them in the continuously. Minimum order quantity issues must be solved. The supplier
must be able to adjust to the changes fast and also he must be able to keep the correct quality
from batch to the other. And there may be much more problems to overcome. To overcome
this corporate level involvement is very much required. When achieved this will mutually
benefit both you and your supplier.
4.1.2. JIT Production
JIT manufacturing might be the most talked topic of all lean manufacturing
techniques. This requires very good internal coordination and planning. All the tools we are
going to discuss in this chapter will help achieving this objective. Even within the
manufacturing area, pull demand concepts are used. The items are produced only when they
are required by the process following it. No stocks are maintained. This will reduce the costs
due to WIP. This will also reduce the cycle time of the product, and therefore will improve the
flexibility of the system immensely. This will also reduce the lead time considerably. Quality
defects will be much lower since WIP is very low.
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Achieving JIT manufacturing is again not an easy task. Most of the time this requires a
radical change in the organization. Work will change from the conventional departmental
thinking to the new team thinking. Manufacturing will change from the line system to the
module or work cell based manufacturing. Every problem will cause the system to stop since
there is no WIP to work with. All the problems hidden in the WIP will be revealed. Some
people might not like the system. In short there will be tons of problems to be solved. This
requires some courage and temperament.
It is true to say that most of the problems in achieving JIT manufacturing is has to deal
with the human side of the problem. People do not like to change if there is no motivation to
do so. People will fear about their jobs. They can bring lots of negative thoughts to this. Of
cause negative thoughts are important. Why I am saying this is these negative thoughts mightbring some real problems which we have never addressed before.
You will have to deal with these problems very carefully. One thing that you have to
do first of all is driving out the fear with this change. Specially regarding their jobs. You have
to take their participation in the process and let them to understand themselves that this is not
something that should be feared about. You have to motivate people by continuous education
about the new system. One smart idea may be to use the same names which they are familiar
before for the new systems. For an example use the word bin card instead of a kanban card.
People will feel immensely comfortable with the names they have been using before. You
also will not lose anything, as far as you are applying the kanban techniques in your
production.
4.1.3. JIT Distribution
Apart from these problems there are very serious of problems which has to be dealt
with transporting the goods. Since there will not be much of a stock to rely on, every load of
goods is very important for smooth production run. Any delay will be very costly.
To achieve a smooth production without any delays in production and to distribute the
goods in small batches to the buyers in continuous basis, it is very important to keep a good
transportation management system. Generally this is known as the JIT distribution. Without
this any of the lean objectives might not be possible. Most often this function is given to a
third party logistic
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Company, who will take care of JIT distribution. On time, uninterrupted data
exchange is very vital in this. Therefore it is advisable of using a electronic way of data
interchange. It is also very much necessary to automate this data transfer function to avoid
any delays and mistakes in duplication.
4.2. Work Cells
Work cell concept is another concept developed with the JIT. Work place is arranged
in to a cell which is in the shape of English letter U. in a work cell there will be 3 -12 people
depending on the job task performed by this cell. There will be many cells which will
complete the total product by working together. People who are in this cell are multi skilled
and can perform multiple tasks according to the requirement. One of the main advantages of
the work cell is the less movement and lesser transportation. Also this will reduce the over
production considerably. This will also give very high flexibility to the entire production
system since changing from one product to another is very easy. Sometimes it may require
changing one work cell to produce a completely new product. Team working culture is very
important in a process like this. Therefore good leadership is very much required. Every
performance is measured in the team basis. Therefore motivation must be there for all the
people working in the cell to work for a common objective.
( Figure: 4.3 )
Work cells
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4.3. Kanban Tooling
Kanban is one of most popular tools in lean manufacturing. This is a simple concept,
but very effective. Kanban mainly focus on the reduction of overproduction. There are mainly
two types of kanbans. They are as below:
Withdrawal kanban
Production kanban
Withdrawal kanban is the common type, which is actually a request from the process
before that. This specifies the quantity that the succeeding process should take from the
process before that. On the other hand production kanban specifies the amount of products to
be made in the next process with the goods created in the process before that.
This might take a form of a simple card which has the details of the product, qty and
the storage location of that particular product. This even may be a sophisticated electronic
data exchange process. No matter what, the final objective must be achieved and it should be
an efficient process.
4.4. Poka-Yoke (Fool proofing)
Poka-Yoke is designing the work process to eliminate human mistakes. Fool proofing
system is a means to create devices that can discover defectives without the workers having to
be attentive to minute details. The steps for fool proofing are,
If there is a miss step, the device does not allow goods to be mounted to jigs. If a disorder is found in the goods, the device does not allow the machine to start
processing.
If there is a miss step in work process or in motion, it is automatically adjusted, andthe device will allow processing to proceed.
The disorder that has occurred in preceding process is examined at the next process,and the device will stop defectives.
If a certain operation is forgotten or stopped, the device does not allow the next operation to
begin.
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4.5. Workplace Organization (5 S)
This tool is a systematic method for organizing and standardizing the work place. Its one of
the simplest Lean tools to implement, provides immediate return on investment, crosses all industry
boundaries, and is applicable to every function with an organization. One of the most fundamental and
widely applied tools of Lean Manufacturing is 5S. The benefits of 5S are:
It can be done today Everyone can participate Waste is made visible Has a wide area of impact
o Improves set up timeso Improves qualityo Improves safetyo Improves moraleo Improves productivity
There is an order and logic to how 5S is carried out. It doesnt make sense to start by
arranging things neatly, if most of those things are not needed. The five S words below are the steps
of 5S.
4.5.1. Sort
It is about removing all items that are not required or are unnecessary within a period
ahead. Such items are waste, or lead to waste. They take up space, lead to extra walking
around, and lead to waste of time whilst searching for needed items buried under piles of less
important material.
4.5.2.Straighten
It is about having things easy to hand, labeled, classified and easily visible. Shadow
boards may be used for tools, books arranged by topic, shelves not too high, wheels on carts,
heavy low and light high, colour coded connections and pipes.
It has a direct impact on productivity-Searching for lost papers and tools should be
eliminated. And time wasted should be cut by careful location of tools and materials.
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4.5.3. Scrub (Sweep)
Clean and check regularly is about keeping things clean and ready to go. This step
follows clean and orderliness. It needs to be done daily. Routine maintenance may be in
cooperatedoil every day, replace after 5000 sheets, and air craft style checks where items
are checked at the start of every shift. One important activity is identifying which
maintenance activities are the responsibility of the ordinary staff, and which are the
responsibility of the specialist maintenance staff.
4.5.4. Standardize
It refers to engendering the habits of workplace procedures. It is about the
establishment and maintenance of standards. The first standard is to ensure that the previous
3Ss are in place and maintained. Standards should be kept line side and be diagrammatic o r
written, but never verbal. Standard procedures can be color coded to match the product, which
carries a label of matching colour. When an engineering change occurs, a number on the
product should match the number on the standard sheet. Any standard should cover not only
what to do when things are normal, but also what to do if things go wrong.
4.5.5Self Discipline
It is to make sure that the activities are kept going. This amounts to identifying
responsible people, setting the frequency of review, and maintaining a visual record for
important equipment. Prevention is the watchword. But even better than prevention is
falsifying, whereby inspection is automatic and a warning occurs. Examples are automatic
counts on cutting, showing a light when tool change is required, or automatic backup of hard
disk.
Management participation and interest is vital to keep a 5S programs going.
Expectation and example are important. Management must be seen to practice 5S themselves,
and to maintain commitment.
4.6. Total Productive Maintenance (TPM)
It is a concept of productive maintenance aimed at achieving overall effectiveness of
the production system through the involvement of all the people in the organization. It
consists of a companywide equipment maintenance program covering the entire equipment
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life cycle. The goal of TPM is to minimize downtime due to maintenance, and maximize
machine uptime. One of the key elements of TPM is autonomous maintenance where the
operators are responsible for maintaining their own equipment.
TPM stages are break down maintenance, preventive maintenance, productive
maintenance, and total productive maintenance.
TPM = Productive Maintenance + Small Group Activities
MP = Maintenance Prevention
PM = Preventive Maintenance
MI = Maintainability Improvement
TPM capitalizes on proactive and progressive maintenance methodologies and calls
upon the knowledge and cooperation of operators, equipment vendors, engineering, and
support personnel to optimize machine performance. Results of this optimized performance
include; elimination of breakdowns, reduction of unscheduled and scheduled downtime,
improved utilization, higher throughput, and better product quality. Bottom-line results
include; lower operating costs, longer equipment life, and lower overall maintenance costs
4.7. Value Stream Mapping
Value stream mapping is usually the first step in the evaluation of an existingmanufacturing process. A Value Stream Map is a visual documentation of the process flow,
( The Relationship b/w TPM, Productive Maintenance & Preventive Maintenance )
Fi ure: 4.4
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both material and information flows are depicted. It is used to provide a snapshot of the
"Present State" of your manufacturing process. Producing this present state flow diagram will
help identify all of the value adding and non-value adding steps within your process. Once
this present state map is completed, a company will clearly see where the opportunities are for
eliminating the non-value adding steps. The "Future State" Map of a process is then created
showing the improved, streamlined flow. Using this method will allow a company to look at
the "Big Picture" of a manufacturing process. Value Stream Mapping doesn't require any
special software tools; everything should be drawn by hand and in pencil.
4.8. Setup Reduction
It is the technique of time to change a process from running one specific type of
product to another. The purpose for reducing changeover time is not for increasing production
capacity, but to allow for more frequent changeovers in order to increase production
flexibility.
Setup reduction is driven by the need of being able to change over a given process to
produce a different product in the most efficient manner. Reducing Setup (or Change Over) is
the lean manufacturing technique allowing the mixing of production/products without slowing
output or creating higher costs associated with non-value adding activity. Changeovers add no
value and therefore should be minimized. The goal is to reduce and/or eliminate downtime
due to setups and changeovers. The setup process should be viewed from two different
perspectives, one is Internal, steps required to be completed when the machine is stopped
versus external steps accomplished offline while the machine is in operation. Quick
Changeover will increase productivity, reduce lead-time, lower total costs, and increase
flexibility to adapt to a changing market and/or product mix.
4.9.Batch Size Reduction
Historically, manufacturing companies have operated with large batch sizes in order to
maximize machine utilization, assuming that changeover times were fixed and could not be
reduced. Because Lean calls for the production of parts to customer demand, the ideal batch
size is ONE. However, a batch size of one is not always practical, so the goal is to practice
continuous improvement to reduce the batch size as low as possible. Reducing batch sizes
reduces the amount of work-in-process inventory (WIP). Not only does this reduce inventory-
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carrying costs, but also production lead-time or cycle time is approximately directly
proportional to the amount of WIP. Therefore, smaller batch sizes shorten the overall
production cycle, enabling companies to deliver more quickly and to invoice sooner (for
improved Cash flow). Shorter production cycles increases inventory turns and allows the
company to operate profitably at lower margins, which enables price reductions, which
increases sales and market share.
4.10. Total Quality Management
Total quality management is a management system used to continuously improve all
areas of a companys operation. TQM is applicable to every operation in the company and
recognizes the strength of employee involvement.
4.11. Pull System
Manufacturing system can be divided into two as below:
4.11.1 Push System
Here the products are made according to the market forecast and not according to the
current demand. So here the information flow is in the same direction as the product flow. So
there may chance of piling of finished goods as there are always fluctuation in demand. Thus
the product is pushed through the production line.
4.11.2 Pull System
Here the product is made according to the customer demand. So the information of the
quantity and type of product flow in the opposite direction to that of the product. Here no
piling of finished products occurs as the production is according to the customer demand.
Hence the customer pulls the product through the production line.
( Figure: 4.5 )
( Push & Pull system )
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CHAPTER 5 CHARACTERISTICS
5.1. Malty skilled workforce
In order to have smoothed production, it is necessary that the worker be skilled in a
number of functions. The use of mono skilled and mono-function worker in industry, leads to
much underutilization of labour/machinery. Small fluctuations in the demand can be taken
care of by lean production, through use of an elongated shift working and deployment of
skilled workers. If the demand is slightly lower, the work is finished early and the rest of the
period is used for either workers rest, or activity such as practicing set-ups, preventive
maintenance etc.
5.2. Short set up time
The characteristics of smoothed production is to have a short set up time, because it
assumes that there is very little time loss between different changeovers. The aim is to please
the customer by producing only those products which he has ordered. We cannot complain
about the frequency of die- exchange. So the alternative left is to shorten the time spent for
exchange of die. Through constant efforts by use of quality circles, set up times have been
reduced to single-digit or even less than one minute. Known as single set-ups and one-
touch-set-ups respectively.
5.3. Employee involvements and empowerment
It involves organizing workers by forming teams and giving them training and
responsibility to do many specialized tasks, for house keeping, quality inspection, minor
equipment repair and rework. And also allowing them to meet to discuss problems and find
ways to improve the process.
5.4. Supplier involvement
The manufacturer treats its suppliers as a long term partners. They often must be
trained in ways to reduce set up times, inventories, defects, machine breakdowns, etc. in order
to enable them to take responsibility for delivering the best.
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5.5. Improved quality through immediate feedback
Before lean manufacturing there was batch method of production. So an error in one
of the machining operation or material defect was identified only after completing of
particular process. Also the same defective component was machine to final stage and after
that error was identified. This caused rejection of total batch quantity and wastage of
resources.
Because of lean manufacturing smooth flow of material/production resulted. The error
or defect in previous manufacturing operation is immediately identified by operator and he
gives feedback. In this way continuous and batch rejection is avoided. Effects in materials like
cracks, blow holes, excess are pointed out quickly. Thus there is continuous quality
improvement due to lean manufacturing. The overall effect is less rejection.
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CHAPTER 6 BENEFITS OF JIT & LEAN
The benefits of implementing Lean [2] can be broken down into three broad
categories; Operational, Administrative, and Strategic Improvements. Even to this day, most
organizations that implement Lean do so the operational improvements, primarily because of
the perception that Lean only applies to the operations side of the business. However, from
our experiences, Leans administrative and strategic benefits are equally impressive. Some of
Leans benefits are summarized below.
6.1. Operational Improvement
The NIST Manufacturing Extension Partnership recently surveyed forty of their
clients who implemented Lean Manufacturing. Typical improvements were reported as
follows:
Lead Time (Cycle Time) reduced by 90%
Productivity increased by 50%
Work-In-Process Inventory reduced by 80%
Quality improved by 80%
Space Utilization reduced by 75%
6.2. Administrative Improvements
A small sample of specific improvements in administrative functions is as follow:
Reduction in order processing errors
Streamlining of customer service functions so that customers are no longer placed on hold
Reduction of paperwork in office areas
Reduced staffing demands, allowing the same number of office staff to handle larger
numbers of orders
Documentation and streamlining of processing steps enables the out-sourcing of non-
critical functions, allowing the company to focus their efforts on customers needs Reduction
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of turnover and the resulting attrition costs.
6.3. Strategic Improvements
Many companies who implement Lean do not adequately take advantage of theimprovements. Highly successful companies will learn how to market these new benefits and
turn them into increased market share. One specific example involves a mid western
manufacturer of a common health care product. Of approximately forty U.S. competitors, the
third largest company in the industry decided to implement Lean manufacturing principles.
The industry average lead-time was fifteen days, and this company was no different. At the
end of the project, Company #3s average lead-time was four days, with no products shipped
in less than seven days. In order to capitalize upon these improvements, the company began amarketing campaign, advertising that customers would receive the product in ten days, or the
order would be FREE. Sales volume increased by 20% almost immediately. After making the
appropriate improvements to handle the new demand, they company initiated another
marketing campaign; for only a 10% premium, they would ship within seven days. Again,
sales volume increased (by only 5%) because new customers wanted the product within seven
days, but more than 30% of existing customers also paid the premium, even they were already
receiving the product in less than seven days. The end result was that the company increased
revenues by almost 40% with no increase in labor or overhead costs. Another key benefit was
that the company was able to invoice customers eleven days sooner than before, greatly
improving cash flow.
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CHAPTER 7 TRADITIONAL Vs JIT & LEAN
For years manufacturers have created products in anticipation of having a market for
them. Operations have traditionally been driven by sales forecasts and firms tended tostockpile inventories in case they were needed. A key difference in JIT & Lean
Manufacturing is that it is based on the concept that production can and should be driven by
real customer demand. Instead of producing what you hope to sell; JIT & Lean Manufacturing
can produce what your customer wants with shorter lead times. Instead of pushing product to
market, it's pulled there through a system that's set up to quickly respond to customer demand.
JIT & Lean organizations are capable of producing high-quality products
economically in lower volumes and bringing them to market faster than mass producers. JIT
& lean organization can make twice as much product with twice the quality and half the time
and space, at half the cost, with a fraction of the normal work-in-process inventory. JIT &
Lean management is about operating the most efficient and effective organization possible,
with the least cost and zero waste.
7.1 OVERALL ORGANIZATIONAL CHARACTERISTICS
TRADITIONAL MASS
PRODUCTION
JIT & LEAN PRODUCTION
Business Strategy Product-out strategy focused on
exploiting economies of scale of
stable product designs and non-
unique technologies
Customer focused strategy focused
on identifying and exploiting
shifting competitive advantage.
Customer
Satisfaction
Makes what engineers want in large
quantities at statistically acceptable
quality levels; dispose of unused
inventory at sale prices
Makes what customers want with
zero defect, when they want it, and
only in the quantities they order
Leadership Leadership by executive command Leadership by vision and broad
participation
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Organization Hierarchical structures that
encourage following orders and
discourage the flow of vital
information that highlights defects,operator errors, equipment
abnormalities, and organizational
deficiencies.
Flat structures that encourage
initiative and encourage the flow of
vital information that highlights
defects, operator errors, equipmentabnormalities, and organizational
deficiencies.
External Relations Based on price Based on long-term relationships
Information
Management
Information-weak management
based on abstract reports
Information-rich management
based on visual control systems
maintained by all employees
Cultural Culture of loyalty and obedience,
subculture of alienation and labor
strife
Harmonious culture of involvement
based on long-term development of
human resources
Production Large-scale machines, functional
layout, minimal skills, long
production runs, massive
inventories
Human-scale machines, cell-type
layout, multi-skilling, one-piece
flow, zero inventories
Operational
capability
Dumb tools that assume an extreme
division of labor, the following of
orders, and no problem solving
skills
Smart tools that assume
standardized work, strength in
problem identification, hypothesis
generation, and experimentation
Maintenance Maintenance by maintenance
specialists
Equipment management by
production, maintenance and
engineering
Engineering "Isolated genius" model, with little
input from customers and little
respect for production realities.
Team-based model, with high input
from customers and concurrent
development of product and
production process design
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7.2 MANUFACTURING METHODS
TRADITIONAL MASS
PRODUCTION
JIT & LEAN PRODUCTON
Production schedules
are based on
Forecastproduct is
pushed through the facility
Customer Orderproduct is pulled
through the facility
Products manufactured
to
Replenish finished goods
inventory
Fill customer orders (immediate
shipments)
Production cycle times
are
Weeks/months Hours/days
Manufacturing lot size
quantities are
Large, with large batches
moving between
operations; product is sent
ahead of each operation
Small, and based on one-piece flow
between operations
Plant and equipment
layout is
By department function By product flow, using cells or lines
for product families
Quality is assured Through lot sampling 100% at the production source
Workers are typically
assigned
One person per machine With one person handling several
machines
Worker empowerment
is
Lowlittle input into
how operation is
performed
Highhas responsibility for
identifying and implementing
improvements
Inventory levels are Highlarge warehouseof finished goods
Lowsmall amounts betweenoperations, ship often
Flexibility in changing
manufacturing
schedules is
Lowdifficult to handle
and adjust to
Higheasy to adjust to and
implement
Manufacturing costs
are
Rising and difficult to
control
Stable/decreasing and under control
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CHAPTER 8 CONCLUSION
From this study, it is understood that, in this modern competitive world, where only
those industries, which provide maximum customer satisfaction at attracting prices can
succeed, the JIT & Lean manufacturing system plays an important role, as it reduces the
manufacturing time & wastage, during production. Thus it increases the amount of goods
produced and decreases the cost of production of these goods.
This seminar stresses the need to implement JIT & Lean manufacturing technique in
Automobile industries & other modern industries where large-scale production takes place.
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REFERENCES
1. Just in Time - by David Hutchins, Productivity press (India) Pri. Ltd.2. Study of Toyota production system - by Shigeo Shingo3. Toyota Production System - by Yasuhiro Monden4. Just in Time for Today and Tomorrow - by Taiichi Ohno, Setsuo Mito5. Management Guide to Quality and Productivity - John Bicheno, M.R.Gopalan, Wheeler
Publishers.
6. Lean Production-An Innovation Management - by S.Ilangovan, N.Saravanan7. www.leanmanufacturingconcepts.com8. www.mep.org.9. www.ddiworld.com10.www.advancedmanufacturing.com
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