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CHAPTE
R
14
Just-In-Time Systems
Introduction to Operations management
1
Toyota Production System
 The
objective
– Continuous improvement of the production
system (Kaizen)
Introduction to Operations management
2
Toyota Production System
 Elements
of the Toyota System
– Just-in-time
» needed units arrived at the right time in the right
amount
– Kanban system
» a pull system with tight limit on work-in-process
inventory
Introduction to Operations management
3
JIT/Lean Production
Just-in-time: Repetitive production system in
which processing and movement of materials
and goods occur just as they are needed,
usually in small batches
 JIT
is characteristic of lean
production systems
 JIT operates with very little “fat”
Introduction to Operations management
4
JIT Goals
 Eliminate
disruptions
 Make system flexible
 Reduce setup and lead times
 Minimize inventory
 Eliminate waste
Introduction to Operations management
5
Sources of Waste
 Waste
form overproduction
 Waste of waiting time
 Transportation waste
 Inventory waste
 Processing waste
 Waste of motion
 Waste from product defects
Introduction to Operations management
6
JIT Building Blocks
 Product
design
 Process design
 Personnel/organizational
elements
 Manufacturing
planning and control
Introduction to Operations management
7
Building block - Product Design
 Standard
parts
 Modular design
 Quality
Introduction to Operations management
8
Building block - Process Design
 Small
lot sizes
 Setup time reduction
 Manufacturing cells
 Limited work in process
 Quality improvement
 Production flexibility
 Little inventory storage
Introduction to Operations management
9
Benefits of Small Lot Sizes
Reduces inventory
Less rework
Less storage space
Problems are more apparent
Increases product flexibility
Easier to balance operations
Introduction to Operations management
10
JIT - variability reduction
Reduction in S (setup cost)
EOQ 
2DS
H
Q
Introduction to Operations management
11
JIT - Variability reduction
Reduction in safety stock
Safety Stock = ROP -  = z
Introduction to Operations management
12
Building block - Production Flexibility
 Reduce
downtime by reducing
changeover time
 Use preventive maintenance to
reduce breakdowns
 Cross-train workers to help clear
bottlenecks
 Reserve capacity for important
customers
Introduction to Operations management
13
JIT - flexibility
Low setup cost
Flow direction
CCBBBA
ABBACCC
Introduction to Operations management
14
Building block - Personnel/Organizational
Elements
 Workers
as assets
 Cross-trained workers
 Continuous improvement
 Cost accounting
 Leadership/project management
Introduction to Operations management
15
Building Block - Manufacturing Planning
and Control
 Level
loading
 Pull systems
 Visual systems
 Close vendor relationships
 Reduced transaction processing
Introduction to Operations management
16
Pull/Push Systems
 Pull
system: System for moving
work where a workstation pulls
output from the preceding station
as needed. (e.g. Kanban)
 Push system: System for moving
work where output is pushed to the
next station as it is completed
Introduction to Operations management
17
Kanban Production Control System
 Kanban
is the Japanese word for card.
 Paperless production control system
 Authority to pull, or produce comes
from a downstream process.
Introduction to Operations management
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Summary JIT Goals and Building Blocks
Ultimate
A
Goal
balanced
rapid flow
Supporting
Goals
Reduce setup
and lead times
Eliminate waste
Eliminate disruptions
Make the system flexible
Minimize inventories
Product
Design
Process
Design
Personnel
Elements
Manufacturing Planning
Building
Blocks
Introduction to Operations management
19
Benefits of JIT Systems
 Reduced
levels of inventories
 Reduced space requirements
 Increased product quality
 Reduced lead times
 Greater flexibility in product mix
Introduction to Operations management
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Benefits of JIT Systems (cont’d)
 Smoother
production flow
 Increased productivity levels
 Worker participation in problem solving
 Pressure for good vendor relationships
 Reduced need for indirect labor
Introduction to Operations management
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Converting 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
Introduction to Operations management
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Obstacles to Conversion
 Management
may not be committed
 Workers/management may not be
cooperative
 Suppliers may
resist
Introduction to Operations management
23
JIT in Service
The basic goal of the demand flow
technology in the service organization
is to provide optimum response to the
customer with the highest quality
service and lowest possible cost.
Introduction to Operations management
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