Just-in-Time (JIT) or Lean Production is a system that aims to reduce waste by receiving and producing goods only as needed, thereby reducing inventory costs. It coordinates the supply chain through smaller lot sizes, faster setups, and less inventory. Goods are "pulled" through production rather than "pushed" in large batches. Kanban systems use visual signals like cards or empty slots to control production flows and minimize overproduction. The goals of JIT are to eliminate disruptions, increase flexibility, and reduce waste across the supply chain.

1. Just-in-Time/Lean Production
A repetitive production system
in which the processing and movement
of materials and goods occur
just as they are needed!
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2. Pre-JIT: Traditional Mass Production
Big lot sizes
Lots of inventory
”PUSH” material to next
stage
Big purchase shipments
???
Lower
per unit
cost
Big “pushes” of finished goods
to warehouses or customers
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3. Post-JIT: “Lean Production”
Tighter coordination along the supply chain
Goods are pulled along
— only make and ship what is needed
Smaller lots
Faster setups
Smaller shipments Less inventory, storage space
”PULL” material to next stage
Minimal
or no
inventory Goods are pulled out of
holding plant by customer demand
cost
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4. JIT Goals
(throughout the supply chain)
• Eliminate disruptions
• Make the system flexible
• Reduce setup times and lead times
• Minimize inventory
• Eliminate waste
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5. Waste
Definition:
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
President, Toyota
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6. Forms of Waste:
• Overproduction
• Waiting time
• Transportation
• Processing
• Inventory
• Motion
• Product Defects
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7. Inventory as a Waste
• Requires more storage space
• Requires tracking and counting
• Increases movement activity
• Hides yield, scrap, and rework
problems
• Increases risk of loss from theft,
damage, obsolescence
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8. Building Blocks of JIT
• Product design MP
C
 Standard parts Sta
ff OR
G
 Modular design Pro
ce ss De
s ig
n
 Quality Pro
d uct Des
ign
• Process design
• Personnel and organizational elements
• Manufacturing planning and control
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9. Process Design
• “Focused Factories”
• Group Technology
• Simplified layouts with little storage
space
• Minimum setups
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10. Personnel and Organizational
Elements
• Workers as assets
• Cross-trained workers
• Greater responsibility at lower levels
• Leaders as facilitators, not order givers
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11. Planning and Control Systems
• “Small” JIT
• Stable and level schedules
– Mixed Model Scheduling
• “Push” versus “Pull”
– Kanban Systems
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12. Kanban
Uses simple visual signals to control
production
• Examples:
 empty slot in hamburger chute
 empty space on floor
 kanban card
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13. Kanban Example
Workcenter A Workcenter B
Workcenter B uses parts produced by Workcenter A
How can we control the flow of materials so that B always
has parts and A doesn’t overproduce?
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14. Kanban card: Signal to produce
Workcenter A Workcenter B
Kanban Card
When a container is opened by Workcenter B, its kanban card is
removed and sent back to Workcenter A.
This is a signal to Workcenter A to produce another box of parts.
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15. Empty Box: Signal to pull
Workcenter A Workcenter B
Empty box sent back. Signal to pull another full box into
Workcenter B.
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