JIT/Lean Production systems aim to minimize waste by producing and delivering only what is needed when it is needed. This "pull" approach contrasts with traditional "push" systems involving large batch sizes and high inventory levels. Key aspects of JIT include minimizing inventory, continuous improvement, small lot sizes, and close supplier partnerships. Transitioning to JIT requires management commitment, reducing setup times gradually, and preparing for obstacles like resistance from workers or suppliers accustomed to older ways. Benefits include reduced costs, higher quality, flexibility, and better space utilization.

1. JIT/Lean Production
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2. Post World War II
- Growing and rebuilding world economy
- Demand > Supply
- US Manufacturing:
Higher volumes
Capital investment
“Breakthrough” improvements
“The production problem has been solved”
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3. View from Japan
- Very little capital
- War-ravaged workforce
- Little space
- Poor or no raw materials
- Lower demand levels
- Little access to latest technologies
 U.S. methods would not work
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4. Japanese Approach to Operations
- Maximize use of people
- Simplify first, add technology second
- Gradual, but continuous improvement
- Minimize waste (including poor quality)
 Led to the development of the approach known as
Just-in-Time
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5. Some Statistics from 1986
Framingham (GM)
40.7 hours
130 defects
2 weeks
Toyota Takaoka
16 hours
45 defects
2 hours
A comparison of:
- assembly hours
- defects per 100 cars
- average inventory levels
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6. A highly coordinated processing system in
which processing and movement of
materials and goods occur just as they are
needed
The ultimate goal of JIT is a balanced system.
Just-In-Time
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7. Pre-JIT: Traditional Mass Production
Big lot sizes
Lots of inventory
”PUSH” material to next
stage
Lower
per unit
cost
Big purchase shipments
Big “pushes” of finished goods
to warehouses or customers
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8. 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
Less inventory, storage space
”PULL” material to next stage
Minimal
or no
inventory
holding
cost
Smaller shipments
Goods are pulled out of
plant by customer demand
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9. JIT Goals
- Eliminate disruptions
- Make the system flexible
- Reduce setup times and lead times
- Minimize inventory
- Eliminate waste
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10. Waste
:
Waste is „anything other than the minimum amount of
equipment, materials, parts, space, and workers‟ time,
which are absolutely essential to add value to the product.‟
“Shoichiro Toyoda;President, Toyota”
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11. Forms of Waste:
(„muda‟ in Japanese)
- Overproduction
- Waiting
- Unnecessary movement
- Wrong process
- Unnecessary inventory
- Excess motion
- Defects
- Underutilization of employees
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12. 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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13. Examples of Eliminating “Wastes”
Big Bob‟s Automotive Axles:
Wheels bought from
Supplier outsider
Axles made and
assembled in house
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14. “BEFORE”Shipping in Wheels
Bob’s
Wheels
Warehouse
Truck Cost: $500 (from Peoria)
Maximum load of wheels: 10,000
Weekly demand of wheels: 500
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15. Truck Cost: $50 (from Burlington)
Maximum load of wheels: 500
Weekly demand of wheels: 500
What wastes have been reduced?
Bob’s
Wheels
“AFTER”Shipping in Wheels
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16. BEFORE: Making Axles (Different lengths)
Manufacturing Minimum Batch
1,000 Axles
Tool Bin Final Assembly
Push to
Final
Assembly
“Axle Maker”
Setup: 8 hours
Setup cost: $800
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17. BEFORE: Making Axles (Oops!)
Manufacturing Minimum Batch
1,000 Axles
Tool Bin Final Assembly
Push to
Final
Assembly
“Axle Maker”
Setup: 8 hours
Setup cost: $800
Defect: “Axles are not true!”
What is the outcome of
detecting defective axles
at the end?
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18. Manufacturing
Final Assembly
Pull to
Final
Assembly
“Axle Maker”
Setup: 15 min.
Setup cost: $25
Tools next to “Maker”
No
minimum
batch size
AFTER: Making Axles (Different lengths)
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19. After: Making Axles II
(More improvements)
What wastes have
been reduced?
Manufacturing
Final Assembly
Poka-Yoke
Device
“Axle Maker”
Setup: 15 min.
Setup cost: $0
Tools next to “Maker”
Verify Trueness
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20. Building Blocks of JIT
- Product design (Standard parts/Production system)
- Process design (Jidoka /Poka-Yoke/quality/flexibility)
- Personnel and organizational elements (Workers as assets/Cost
accounting/Continuous improvement)
- Manufacturing planning and control (Pull system/Visual
system/Preventive maintenance)
MPC
Staff ORG
Process Design
Product Design
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21. - Smooth flow of work (the ultimate goal)
- Elimination of waste
- Continuous improvement
- Eliminating anything that does not add value
- Simple systems that are easy to manage
- Use of product layouts to minimize moving materials and parts
- Quality at the source
- Poka-yoke
- Preventative maintenance
- Good housekeeping
- Set-up time reduction
- Cross-trained employees
- A pull system
Elements of JIT
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22. Top Management
Long-term planning
Product line decisions
Expansion issues
Middle management
Planning, purchasing
hiring, and capital decisions
Monitor costs
Supervisors
Control activities in specific areas
Monitor quality, delivery, etc.
Direct Labor
Perform predetermined tasks
Technical Staff
Work methods, QC
Process improvements,
MIS
Planning Info
Control Info
Detailed Methods,
Schedules
Classic Organizational View
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23. JIT Organization View
Top Management
Long-term planning
Product line decisions
Expansion issues
Middle management
Planning, with less purchasing,
hiring, and capital decisions
Monitor costs and assist labor
Direct Labor (self-supervising)
Task performance and schedule attainment
Control specific areas of activity
Monitor quality, delivery, etc.
Participate in hiring and continuous
improvement
Technical Staff
Training and Technical
Support
Planning Info
Control Info
TechnicalIdeas
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24. JIT VS Traditional
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
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25. Transitioning to a JIT System
- Get top management commitment
- Decide which parts need most effort
- Obtain support of workers
- Start by trying to reduce setup times
- Gradually convert operations
- Convert suppliers to JIT
- Prepare for obstacles
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26. Obstacles to Conversion
- Management may not be committed
- Workers/management may not be cooperative
- Suppliers may resist
Why?
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27. Benefits of JIT Systems
- Reduced inventory levels
- High quality
- Flexibility
- Reduced lead times
- Increased productivity
- Increased equipment utilization
- Reduced scrap and rework
- Reduced space requirements
- Pressure for good vendor relationships
- Reduced need for indirect labor
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28. Questions ?
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