- Just-in-time (JIT) manufacturing was first developed by Toyota to reduce waste by supplying the right materials to production lines only when needed and in the minimum necessary amounts. It aims to eliminate overproduction and excess inventory that do not add value. - Key aspects of JIT include a pull-based production system controlled through kanban signals, small lot sizes, low setup times, continuous flow, and close partnerships with suppliers. Implementing JIT exposes problems in production so they can be addressed, improving quality over time. It requires stable production schedules and reliable equipment and processes.

1. Just in time technology (JIT)
Presented by
Akash Dutta
Department of Mechanical Engineering
Indian Institute of Technology Guwahati

2. History of JIT
• First developed by Toyota
• Toyota not only applied JIT to its own production but also to its
supplier delivery operations
• Before JIT
o “just in case” production
o Large in-progress inventories to cope with production problems
• Other concepts related to JIT-
o Continuous flow manufacturing…IBM corporation
o Zero inventory production system…General Electric Company
o Zero inventory…American Production and Inventory Control
Society
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3. What is JIT?
• Supplying "what is needed, when it is needed, and in the amount
needed“
• Making "only what is needed, when it is needed, and in the amount
needed.“
The philosophy of JIT:
“the storage of unused inventory is a waste of resources”
Aim:
“the right material, at the right time, at the right place, and in the exact
amount”, without the safety net of inventory
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4. Features of JIT
• Reduction of wastage
• Pull system of production
• Use of kanbans
• Streamlined production
• Flexibility in production
• Low inventories
• Balanced system: Distribution of the workload evenly among
work stations
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5. Reduction of wastes
“Waste is anything other than the minimum amount of equipment, materials,
parts, space, and worker’s time, which are absolutely essential to add value to
the product”
Shoichiro Toyoda
Sources of wastes:
• Overproduction
• Waiting
• Unnecessary transportation
• Inventory
• Inefficient work methods
• Inefficient processing
• Unnecessary motions
• Product defects
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6. Wastes in operation
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7. Wastes in operation
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8. Wastes in operation
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9. Push system of production
• Parts at each workstation are produced irrespective of the need for
them in the downstream workstation
• Pushes the parts through the plant
• More parts get produced than the system can handle
• Large work-in-progress inventory
• Overloaded factory
• Example: material requirement planning (MRP)
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10. Pull system of production
• The order to make and deliver parts at each workstation comes from
the downstream station that uses that part
• Order placed only when parts are about to be exhausted
• Production starts only upon receiving the order
• When implemented through the plant has the effect of pulling parts
through the system
• Minimum work-in-progress inventory
• JIT is based on this system
• Example: Toyota production system
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11. Kanban system
“kan ban”
Card signal
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Signal card
When to make it! When to move it!

12. Two types of kanban signal
1. Production kanban
o authorizes the upstream station to produce a batch of parts
o the parts produced are placed in containers so that the batch
quantity is just sufficient to fill It
o production more than this quantity is not allowed
2. Transportation kanban
o authorizes the movement of a batch of parts to the next
downstream station
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13. How kanban works?
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14. How kanban works?
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15. How kanban works?
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16. How kanban works?
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17. The production kanban signal
It tells us:
 when to make
 what to make
 how much to make
Types:
1. Production card
 Instructs us to make One Container
2. Signal (Triangle)
 Instructs us to produce One Lot
 Used when a work unit does not have the changeover capability
to produce one container for one production card
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18. Production card information
• Store Address
• Kanban Signal Number
• Work Unit Name
• Part Number
• Quantity
• Card Number
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19. Signal (Triangle) Information
• Work Unit Name
• Part Number
• Container Type
• Quantity
• Process Time
• Lot Size
• Order Point
• Kanban Signal Number
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20. Flow of Production Kanban Signals
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21. The transportation kanban signal
It tells us:
 when to move
 what to move
 where to move
 how much to move
Types:
1. Customer Kanban Signal ->Transfers
material from plant to customer
2. Move Kanban Signal -> Transfers material
between work units
3. Supplier Kanban Signal -> Pulls material
from supplier to plant
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22. Customer Kanban signal information
• Supplier
• Quantity
• Supplier Number
• Card Number
• Kanban Signal Number
• Container Type
• Part Number
• Description
• Storage Location
• Storage Address
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23. Flow of Customer Kanban Signal
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24. Move Kanban signal information
• Part Number
• Supplier Name
• Storage Address
• Card Number
• Kanban Signal Number
• Work Unit Name (Customer)
• Quantity per Container
• Line Address (Point of Use)
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25. Flow of Move Kanban Signal
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26. Supplier Kanban signal information
• Supplier Name
• Part Number
• Part Name
• Customer
• Storage Address
• Work Unit Address
• Quantity per Container
• Card Number
• Kanban Signal Number
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27. Flow of Supplier Kanban Signal
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28. Kanban rules
1. Customer (downstream) processes withdraw items in the precise
amounts specified by the Kanban.
2. Supplier (upstream) produces items in the precise amounts and
sequences specified by the Kanban.
3. No items are made or moved without a Kanban.
4. A Kanban should accompany each item, every time.
5. Defects and incorrect amounts are never sent to the next
downstream process.
6. The number of Kanbans is reduced carefully to lower inventories and
to reveal problems.
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29. Streamlined production
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Flow with JIT
Traditional Flow
Customers
Suppliers
Customers
Suppliers
Production Process
(stream of water)
Inventory (stagnant
ponds) Material
(water in
stream)

30. Inventories
• JIT objective: eliminate inventory
• JIT requires
o Small lot sizes
o Low setup time
o Containers for fixed number of parts
• JIT inventory: Minimum inventory (raw material, WIP and finished
goods) to keep the system running
• Tactics
o Use a pull system to move inventory
o Reduce lot size and setup time
o Develop Just-in-Time delivery systems with suppliers
o Use group technology
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31. Problems of keeping inventory
Inventory Hides Problems Just as Water in a Lake Hides Rocks
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Unreliable
supplier
Setup
time
Late
deliveries
Quality
problems
Process
downtime
Scrap
Setup
time
Late
deliveries
Quality
problems
Process
downtime

32. Problems of keeping inventory
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Scrap
Work in process inventory level
(hides problems)
Unreliable
Vendors
Capacity
Imbalances
Scrap
Reducing inventory exposes
problems so they can be solved.
Unreliable
Vendors
Capacity
Imbalances
WIP

33. Quality improvement
• JIT exposes quality problems by reducing inventory
• JIT eliminates number defects with small lots
• JIT requires quality by suppliers
• Team approach and continuous improvement are important for
ensuring quality
• Quality is maintained by the following procedure:
• Find the root cause of the problem, solve permanently and use team
approach in solving the problems
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34. Quality improvement- Jidoka
• Means “Automation with a human touch”
• The word jidoka traces its roots to the invention of the automatic
loom by Sakichi Toyoda, Founder of the Toyota Group
• In 1896, Sakichi Toyoda invented Japan's first self-powered loom
called the "Toyoda Power Loom”
• Weft-breakage automatic stopping device -> automatically stopped
the loom when a thread breakage was detected
• a single operator could be put in charge of numerous looms ->
tremendous improvement in productivity
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35. Jidoka- concept
• Equipment stops when a problem arises
• Operator can visually monitor and efficiently control many machines-> "visual control"
or "problem visualization“
• Toyota plants use a problem display board system called "andon"
• Andon allows operators to identify problems in the production line with only a glance
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36. Requirements for JIT
1. Stable production schedule
2. Small batch sizes and short set-up times
3. On time delivery
4. Defect free components and materials
5. Reliable production equipment
6. Pull system of production control
7. Capable, committed and co-operative work force
8. Dependable supplier base
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37. Comparison of JIT and Traditional Systems
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Factor Traditional JIT
Inventory Much to offset
forecast errors, late
deliveries
Minimal necessary
to operate
Deliveries Few, large Many, small
Lot sizes Large Small
Setup; runs Few, long runs Many, short runs
Vendors Long-term
relationships are
unusual
Partners
Workers Necessary to do the
work
Assets

38. References
1. M. P. Groover, Automation, Production Systems, and Computer-
integrated Manufacturing, 2009, 769-777
2. http://www.toyota.com.au/toyota/company/operations/toyota-
production-system
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39. THANKS