JIT (Just In Time) manufacturing is a philosophy based on eliminating waste and continuously improving productivity. It uses a 'pull' system where actual customer orders trigger production of only what is needed, when it's needed, in the required quantity. Key benefits include lower stock levels and working capital requirements, less waste from obsolete or expired stock, and improved quality from an emphasis on getting production right the first time. However, JIT relies on reliable suppliers and lacks buffer stock for unexpected demand. Kanban is a visual signal system used in JIT to authorize production of new containers/lots and pull materials through the process.

1. JIT (Just In Time)
JIT manufacturing is a philosophy of
manufacturing based on planned
elimination of waste & continuous
improvement of productivity.
Just in time is a ‘pull’ system of
production, so actual orders provide a
signal for when a product should be
manufactured. Demand-pull enables a
firm to produce only what is required, in
the correct quantity and at the correct
time.

2.  Advantages of JIT
1. Lower stock holding means a reduction in storage space which
saves rent and insurance costs
2. As stock is only obtained when it is needed, less working capital is
tied up in stock
3. There is less likelihood of stock perishing, becoming obsolete or
out of date
4. Avoids the build-up of unsold finished product that can occur
with sudden changes in demand
5. Less time is spent on checking and re-working the product of
others as the emphasis is on getting the work right first time
 Disadvantages of JIT
1. Production is very reliant on suppliers and if stock is not
delivered on time, the whole production schedule can be delayed
2. There is no spare finished product available to meet unexpected
orders, because all product is made to meet actual orders –
however, JIT is a very responsive method of production

3. JIT elements
1. Product design element
2. Process design element
3. Personnel/organizational elements
4. Manufacturing planning and control
Three elements of product design are key to JIT systems:
1. Standard parts
2. Modular design
3. Quality
 Personnel Organizational Elements-
1. Workers as assets
2. Cross-trained workers
3. Continuous improvement
4. Cost accounting
5. Leadership/project management

4.  Process Design element-
1. Small lot sizes
2. Setup time reduction
3. Manufacturing cells
4. Limited work in process
5. Quality improvement
6. Production flexibility
7. Little inventory storage
 Manufacturing Planning and Control
Five elements of manufacturing planning and control are
particularly important for JIT systems:
1. Level loading
2. Pull systems
3. Visual systems
4. Close vendor relationships
5. Reduced transaction processing

5. Kanban
 Kanban is the Japanese word for card
 The card is an authorization for the next
container of material to be produced
 A sequence of kanbans
pulls material through
the process
 Many different sorts of
signals are used, but
the system is still called
a kanban

6. Kanban
1. User removes a
standard sized
container
2. Signal is seen by
the producing
department as
authorization to
replenish
Signal marker
on boxes
Figure 16.8 Part numbers
mark location

7. Kanban
Kanban Finished Customer
goods order
Work
cell
Ship
Raw Kanban Final Kanban
Material assembly
Supplier
Kanban Kanban
Sub-
Purchased assembly
Parts Kanban
Supplier
Figure 16.9

8. More Kanban
 When the producer and user are not in
visual contact, a card can be used
 When the producer and user are in visual
contact, a light or flag or empty spot on
the floor may be adequate
 Since several
components may
be required,
several different
kanban techniques
may be employed

9. More Kanban
 Usually each card controls a specific
quantity or parts
 Multiple card systems may be used if
there are several components or
different lot sizes
 In an MRP system, the schedule can
be thought of as a build authorization
and the kanban a type of pull system
that initiates actual production

10. The Number of Kanban Cards
or Containers
 Need to know the lead time needed to
produce a container of parts
 Need to know the amount of safety
stock needed
Demand during Safety
Number of kanbans lead time + stock
(containers) =
Size of container

11. Number of Kanbans Example
Daily demand = 500 cakes
Production lead time = 2 days
(Wait time +
Material handling time +
Processing time)
Safety stock = 1/2 day
Container size = 250 cakes
Demand during lead time = 2 days x 500 cakes = 1,000
1,000 + 250
Number of kanbans = 250 =5

12. Advantages of Kanban
 Allow only limited amount of faulty or
delayed material
 Problems are immediately evident
 Puts downward pressure on bad
aspects of inventory
 Standardized containers reduce
weight, disposal costs, wasted space,
and labor