Transcript Production and Operations Management: Manufacturing and

Operations Management
For Competitive Advantage
Operations Management
For Competitive Advantage
Chapter 10
Just-in-Time and
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Operations Management
For Competitive Advantage
Chapter 10
Just-in-Time and Lean Systems

JIT Defined

The Japanese Approach to Productivity

JIT Implementation Requirements

JIT in Services
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Just-In-Time (JIT)
Defined
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JIT can be defined as an integrated set of
activities designed to achieve high-volume
production using minimal inventories (raw
materials, work in process, and finished goods).
JIT also involves the elimination of waste in
production effort.
JIT also involves the timing of production
resources (e.g., parts arrive at the next
workstation “just in time”).
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Exhibit 10.1
JIT Demand-Pull Logic
Fab
Vendor
Fab
Vendor
Fab
Vendor
Fab
Vendor
Sub
Customers
Final
Assembly
Sub
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The Japanese Approach to Productivity





Imported technologies
Efforts concentrated on shop floor
Quality improvement focus
Elimination of waste
Respect for people
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Waste in Operations
(1) Waste from overproduction
(2) Waste of waiting time
(3) Transportation waste
(4) Inventory waste
(5) Processing waste
(6) Waste of motion
(7) Waste from product defects
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Minimizing Waste:
Focused Factory Networks
Coordination
System Integration
Final Assembly
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Minimizing Waste:
Group Technology (Part 1)

Using Departmental Specialization for plant layout can cause a lot of
unnecessary material movement.
Saw
Saw
Saw
Grinder
Grinder
Heat Treat
Lathe
Lathe
Lathe
Press
Press
Press
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Minimizing Waste:
Group Technology (Part 2)

Revising by using Group Technology Cells can reduce movement and
improve product flow.
Grinder
Saw
1
2
Lathe
Lathe
Press
Lathe
Press
Heat Treat
Grinder
Saw
Lathe
A
B
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Minimizing Waste:
Uniform Plant Loading
Suppose we operate a production plant that produces a single
product. The schedule of production for this product could be
accomplished using either of the two plant loading schedules below.
Not uniform
Jan. Units
Feb. Units
Mar. Units
Total
1,200
3,500
4,300
9,000
or
Uniform
Jan. Units
Feb. Units
Mar. Units
Total
3,000
3,000
3,000
9,000
How does the uniform loading help save labor costs?
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Minimizing Waste: Just-In-Time
Production
WHAT IT IS
• Management philosophy
• “Pull” system though the plant
WHAT IT REQUIRES
• Employee participation
•
•
•
•
Industrial engineering/basics
Continuing improvement
Total quality control
Small lot sizes
Exhibit 10.3
WHAT IT DOES
• Attacks waste
• Exposes problems and bottlenecks
• Achieves streamlined production
WHAT IT ASSUMES
• Stable environment
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Minimizing Waste: Inventory
Hides Problems
Machine
downtime
Scrap
Work in
process
queues
(banks)
Paperwork
backlog
Vendor
delinquencies Change
orders
Engineering design
redundancies
Inspection
backlogs
Exhibit 10.4
Example: By identifying
defective items from a
vendor early in the
production process the
downstream work is
saved.
Design
backlogs
Decision
backlogs
Example: By identifying
defective work by
employees upstream,
the downstream work is
saved.
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Exhibit 10.6
Minimizing Waste:
Kanban Production Control Systems
Withdrawal kanban
Machine
Center
Storage
Part A
Production kanban
Storage
Part A
Assembly
Line
Material Flow
Card (signal) Flow
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Determining the Number of Kanbans
Needed

Setting up a kanban system requires
determining the number of kanbans (or
containers) needed.
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Each container represents the minimum
production lot size.
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An accurate estimate of the lead time
required to produce a container is key to
determining how many kanbans are
required.
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The Number of Kanban Card Sets
Expected demand during lead time  Safety stock
k
Size of the container
dL(1  S )

C
k = Number of kanban card sets (a set is a card)
d = Average number of units demanded over some time period
L = lead time to replenish an order (same units of time as demand)
S = Safety stock expressed as a percentage of demand during lead time
C = Container size
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Example of Kanban Card
Determination: Problem Data
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A switch assembly is assembled in batches of 4 units
from an “upstream” assembly area and delivered in a
special container to a “downstream” control-panel
assembly operation.
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The control-panel assembly area requires 5 switch
assemblies per hour.
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The switch assembly area can produce a container
of switch assemblies in 2 hours.
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Safety stock has been set at 10% of needed
inventory.
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Example of Kanban Card
Determination: Calculations
Expected demand during lead time  Safety stock
k
Size of the container
dL(1  S ) 5(2)(1.1)


 2.75, or 3
C
4
Always round up!
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Respect for People

Level payrolls
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Cooperative employee unions
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Subcontractor networks
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Bottom-round management style
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Quality circles (Small group involvement
activities)
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JIT Requirements: Design
Flow Process
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Link operations
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Balance workstation capacities
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Relayout for flow
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Emphasize preventive maintenance
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Reduce lot sizes
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Reduce setup/changeover time
See Exhibit 10.8
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JIT Requirements: Total Quality
Control
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Worker responsibility
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Measure SQC
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Enforce compliance
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Fail-safe methods
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Automatic inspection
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JIT Requirements: Stabilize Schedule
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Level schedule
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Underutilize capacity
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Establish freeze windows
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JIT Requirements: Kanban-Pull
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Demand pull
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Backflush
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Reduce lot sizes
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JIT Requirements: Work with Vendors
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Reduce lead times
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Frequent deliveries
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Project usage requirements
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Quality expectations
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JIT Requirements: Reduce
Inventory More
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Look for other areas
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Stores
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Transit
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Carousels
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Conveyors
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JIT Requirements: Improve
Product Design
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Standard product configuration
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Standardize and reduce number of parts
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Process design with product design
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Quality expectations
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JIT in Services (Examples)
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Organize Problem-Solving Groups
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Upgrade Housekeeping
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Upgrade Quality
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Clarify Process Flows
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Revise Equipment and Process
Technologies
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JIT in Services (Examples)
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Level the Facility Load
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Eliminate Unnecessary Activities
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Reorganize Physical Configuration
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Introduce Demand-Pull Scheduling
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Develop Supplier Networks
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