JUST IN TIME SYSTEMS
Figen KAS
Dokuz Eylul University
Industrial Engineering Department
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WHAT IS JUST IN TIME?
Just-in-time (JIT) is easy to grasp
conceptually, everything happens just-intime. For example consider my journey to
work this morning, I could have left my
house, just-in-time to catch a bus to the train
station, just-in-time to catch the train, just-intime to arrive at my office, just-in-time to pick
up my lecture notes, just-in-time to walk into
this lecture theatre to start the lecture.
Conceptually there is no problem about this,
however achieving it in practice is likely to be
difficult!
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In a manufacturing operation
component parts could
conceptually arrive just-intime to be picked up by a worker
and used. So we would at a stroke
eliminate any inventory of parts, they would
simply arrive just-in-time!
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Similarly we could produce finished
goods just-in-time to be handed to a
customer who wants them. So, at a
conceptual extreme, JIT has no need for
inventory or stock, either of raw materials
or work in progress or finished goods.
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Obviously any sensible person will
appreciate that achieving the
conceptual extreme outlined above
might well be difficult, or impossible, or
extremely expensive, in real-life.
However that extreme does illustrate
that, perhaps, we could move an
existing system towards a system with
more of a JIT element than it currently
contains.
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HISTORY
JIT originated in Japan. Its introduction as a
recognised technique/philosophy/way of working is generally
associated with the Toyota motor company, JIT being initially
known as the "Toyota Production System".
Within Toyota Taiichi Ohno is most commonly credited as
the father/originator of this way of working. The beginnings of
this production system are rooted in the historical situation
that Toyota faced. After the Second World War the president
of Toyota said "Catch up with America in three years,
otherwise the automobile industry of Japan will not survive".
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At that time one American car worker produced
approximately nine times as much as a Japanese car
worker. Taiichi Ohno examined the American industry and
found that American manufacturers made great use of
economic order quantities - the traditional idea that it is
best to make a "lot" or "batch" of an item (such as a
particular model of car or a particular component) before
switching to a new item. They also made use of economic
order quantities in terms of ordering and stocking the
many parts needed to assemble a car.
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BENEFITS OF JIT
Reduced operating costs.
 Greater performance and throughput.
 Higher quality.
 Improved delivery.
 Increased flexibility and
innovativeness.

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THE JIT STRATEGY
By taking a JIT approach to inventory and
product handling, companies can often cut
costs significantly. Inventory costs contribute
heavily to the company expenses, especially
in manufacturing organizations. By
minimizing the amount of inventory you hold,
you save space, free up cash resources, and
reduce the waste that comes from
obsolescence.
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JIT SYSTEMS
To facilitate a JIT approach, you need a
variety of systems in place. The most
notable is a kanban. This is a Japanese
approach to ensuring a continuous supply
of inventory or product. Kanbans were
designed to support the JIT philosophy.
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JIT also exists in concert with
continuous improvement systems. Total
Quality Management and Six Sigma are
overarching programs that help you take
a detailed look at every point of the
production process and identify ways to
make improvements. By applying JIT,
you are continuously monitoring the
production process. This gives you
opportunities for making the production
process smoother and more efficient.
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KANBAN SYSTEM
http://www.youtube.com/watch?v=VaOUWsZl6
So
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Rules:
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Every product comming out of fabrication is
associated to a kanban card and conversely.
A product is manufactured only to be associated
to a kanban card, meaning if no stand alone
kanban cards is waiting for its product, no
manufacturing.
A kanban card is physicaly located on the
product, or waiting for it at production. Corrolary:
if a kanban card is not in front of the machine,
it's on the product.
Consummer picking a product leaves the
kanban. This isolated kanban become an order
for a new product to replace the one wich was
just picked up.
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1. No kanban in front of machine means no order,
so no production.
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2. Kanban(s) in front of machine means as many
orders than kanban cards, so production is
required for equivalent quantity.
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3. As soon as a product is manufactured, kanban is
associated.
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If many kanban cards wait in front of machine, it
means equivalent number of products have been
picked-up by consummer. It is time to manufacture
the same quantity of products.
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JIT AND STAKEHOLDER
RELATIONSHIPS
With JIT, it is necessary that you build
strong ties with your supply chain. This will
ensure that you have access to the
supplies you need when you need them.
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With a secure source of supplies, you
can continue to make improvements in
your production and inventory systems.
This helps you to increase your
responsiveness to customer demand. If
you need to ramp up production, you can
be confident knowing your suppliers will
help you.
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Custom orders are simpler with a JIT
system. Instead of the customer's widget
being built six months in advance and
waiting on a shelf, it is built when it's
ordered. By delivering product "just in
time," you allow for last-minute changes.
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
Essentially, JIT allows your company to
get the right products to the right
customers at the right time. In many
industries, this can give you a huge
competitive advantage, at the same time
that it helps you save a large amount of
money.
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