Production and Operations Management: Manufacturing and Services

1
Chapter 12
Lean Manufacturing
2
Learning Objectives
12-2

• After completing the chapter you will
• Learn how a production pull system works
• Study Toyota Production System concepts
• Learn about how value stream mapping can be used
  to identify wasteful activities
• See how Kanban cards can be used to control a
  pull system
• Understand how to accomplish lean production
• See examples of lean concepts applied to service
  systems

3
Lean Production
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• Lean Production 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)
• Lean Production also involves the elimination of
  waste in production effort
• Lean Production also involves the timing of
  production resources (i.e., parts arrive at the
  next workstation just in time)

4
Pull System
Here the customer starts the process, pulling an
inventory item from Final Assembly
Then sub-assembly work is pulled forward by that
demand
The process continues throughout the entire
production process and supply chain
5
Features of Lean Production
6
The Toyota Production System
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• Based on two philosophies
• 1. Elimination of waste
• 2. Respect for people

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Elimination of Waste
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• Focused factory networks
• Group technology
• Quality at the source
• JIT production
• Uniform plant loading
• Kanban production control system
• Minimized setup times

8
Minimizing Waste Focused Factory Networks
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These are small specialized plants that limit the
range of products produced (sometimes only one
type of product for an entire facility)
Some plants in Japan have as few as 30 and as
many as 1000 employees
Coordination
System Integration
9
Minimizing Waste Group Technology (Part 1)
12-9
Note how the flow lines are going back and forth

• Using Departmental Specialization for plant
  layout can cause a lot of unnecessary material
  movement

Saw
Saw
Grinder
Saw
Grinder
Heat Treat
Lathe
Press
Press
Lathe
Lathe
Press
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Minimizing Waste Group Technology (Part 2)
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• Revising by using Group Technology Cells can
  reduce movement and improve product flow

Grinder
2
1
Press
Lathe
Lathe
Saw
Heat Treat
Grinder
Press
A
B
Lathe
Lathe
Saw
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Minimizing Waste Uniform Plant Loading
(heijunka)
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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?
12
Minimizing Waste Inventory Hides Problems
12-12
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Minimizing Waste Kanban Production Control
Systems
12-13
This puts the system back were it was before the
item was pulled
Once the Production kanban is received, the
Machine Center produces a unit to replace the one
taken by the Assembly Line people in the first
place
Withdrawal kanban
Storage Part A
Storage Part A
Machine Center
Assembly Line
Production kanban
Material Flow Card (signal) Flow
The process begins by the Assembly Line people
pulling Part A from Storage
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Respect for People
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• Level payrolls
• Cooperative employee unions
• Subcontractor networks
• Bottom-round management style
• Quality circles (Small Group Involvement
  Activities or SGIAs)

15
Toyota Production Systems Four Rules
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• All work shall be highly specified as to content,
  sequence, timing, and outcome
• Every customer-supplier connection must be
  direct, and there must be an unambiguous
  yes-or-no way to send requests and receive
  responses
• The pathway for every product and service must be
  simple and direct
• Any improvement must be made in accordance with
  the scientific method, under the guidance of a
  teacher, at the lowest possible level in the
  organization

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Lean Implementation Requirements Design Flow
Process
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• Link operations
• Balance workstation capacities
• Redesign layout for flow
• Emphasize preventive maintenance
• Reduce lot sizes
• Reduce setup/changeover time

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Lean Implementation Requirements Total Quality
Control
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• Worker responsibility
• Measure SQC
• Enforce compliance
• Fail-safe methods
• Automatic inspection

18
Lean Implementation Requirements Stabilize
Schedule
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• Level schedule
• Underutilize capacity
• Establish freeze windows

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Lean Implementation Requirements Kanban-Pull
12-19

• Demand pull
• Backflush
• Reduce lot sizes

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Lean Implementation Requirements Work with
Vendors
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• Reduce lead times
• Frequent deliveries
• Project usage requirements
• Quality expectations

21
Lean Implementation Requirements Reduce
Inventory More
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• Look for other areas
• Stores
• Transit
• Carousels
• Conveyors

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Lean Implementation Requirements Improve Product
Design
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• Standard product configuration
• Standardize and reduce number of parts
• Process design with product design
• Quality expectations

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Lean Implementation Requirements Concurrently
Solve Problems
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• Root cause
• Solve permanently
• Team approach
• Line and specialist responsibility
• Continual education

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Lean Implementation Requirements Measure
Performance
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• Emphasize improvement
• Track trends

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Lean in Services (Examples)
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• Organize Problem-Solving Groups
• Upgrade Housekeeping
• Upgrade Quality
• Clarify Process Flows
• Revise Equipment and Process Technologies

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Lean in Services (Examples)
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• Level the Facility Load
• Eliminate Unnecessary Activities
• Reorganize Physical Configuration
• Introduce Demand-Pull Scheduling
• Develop Supplier Networks

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Question Bowl
12-27

• Lean Production seeks to achieve high volume
  production using which of the following?
• Minimal inventory of raw materials
• Minimal inventory of work-in-process
• Minimal inventory of finished goods
• All of the above
• None of the above

Answer d. All of the above
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Question Bowl
12-28

• In the Toyota Production System, the elimination
  of waste involves which of the following?
• Overproduction
• Waiting time
• Transportation
• All of the above
• None of the above

Answer d. All of the above
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Question Bowl
12-29

• In the Pull System the partner that begins the
  process of pulling is which of the following?
• Customers
• Vendors
• Fabrication personnel
• CEO
• All of the above

Answer a. Customer
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Question Bowl
12-30

• A Lean Production program requires which of the
  following?
• Employee participation
• Total quality control
• Small lot sizes
• Continuing improvement
• All of the above

Answer e. All of the above (Also included in
Industrial engineering/basics)
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Question Bowl
12-31

• Inventory has been known to hide which of the
  following production problems?
• Scrap
• Vendor delinquencies
• Decision backlogs
• All of the above
• None of the above

Answer d. All of the above
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Question Bowl
12-32

• When trying to implement Lean system a
  stabilized schedule includes which of the
  following?
• Demand pull
• Backflush
• Fail-safe methods
• All of the above
• None of the above

Answer e. None of the above (These include
level schedule, underutilization capacity, and
establish freeze windows.)
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End of Chapter 12
12-33