Transcript Just-In-Time Chapter 3

Just-In-Time
Chapter 3
JIT Overview

JIT is both a management philosophy and
a set of operational techniques.
• An element of the Toyota’s Production System
(VBW, Figure 3.17)

The philosophy is based on:
• Planned elimination of all waste
• Continuous improvement of productivity
Sources of Waste

Overproduction (inventory)

Defects

Personnel

Equipment

Space

Time (inefficiency)

Utilities
Major Elements of JIT

Carry inventory only when needed

Improve quality to zero defects

Reduce setup times and lot sizes.

Focus on continual improvement.

Make efforts to involve workers and use
their knowledge to a greater extent.

Achieve improvement at minimum cost
JIT in Manufacturing

JIT makes major changes in the actual
practice of manufacturing by reducing:
• Complexity of detailed material planning.
• Need for shop-floor tracking.
• Work-in-process inventories.
• Transactions associated with shop-floor and
purchasing systems.
JIT in Services

Synchronize and balance information and
workflow

Increase process visibility

Continuously improve processes

Eliminate all waste (including paperwork)

Increase resource flexibility
JIT and MPC: the System
(VBW, figure 3.1)
Resource
planning
Detailed capacity
planning
Shop-floor
systems
Production
planning
Demand
management
Master production
scheduling
Front end
Detailed material
planning
Material and
capacity plans
Engine
Vendor systems
Back end
JIT and MPC

Front end:
• Level capacity loading

Engine:
• Reduce number of part numbers planned.
• Reduce number of levels in the BOM.

Back end:
• Focus on simplicity—shop-floor and purchasing.
• Backflushing.
JIT and MPC Building Blocks
(Table 3.1, VBW, p. 77)

Product design
• Standard parts, product simplification, modular design,
robust design, scheduled design changes, design quality

Process design
• Band width—surge capacity to accommodate product
mix and demand variations.
Process flexibility
•
• Setup time reduction
• Cellular system
JIT and MPC Building Blocks
(Table 3.1, VBW, p. 77)

Human/organizational elements
• Whole person concept—continual learning and
improvement.
Cross-training
•
• Motivation and empowerment

Manufacturing planning/control
• Pull system
• Visibility
• Simplified planning and control
JIT Example—Muth Pots


Leveling the production
Pull system introduction
• Material movements and production authorized by
•
•



signal of need from a “downstream” work center.
Schedule must be “frozen” for a period of time.
Determine the container size/capacity/number.
Product design
Process design
Bill of materials implications
JIT Applications

Single-card kanban system (Figure 3.16, p. 90)

Two-card kanban system (Toyota)
• Transport, or conveyance, card.
• Production card.

Two-bin or three-bin system

Kanban cards replace all work orders and move
tickets.

Kanban cards may be used with suppliers.
Calculating Number of Kanbans
DL 1   
y
a





Y=no. of kanbans
D=demand/unit of time [800/day]
L=lead time [2 hours=0.25 days]
a=container capacity [20]
=safety stock [25%]
800 * 0.251  .25
 12.5  13cards
20
Control Through Signaling

Simplicity

Use different methods – kanban, container,
tennis balls, computerized display board
(Andon board), etc.

Planning to schedule/producing to pull signal
• Make or move only with an authorized signal
• First-in, first-out
Workplace Organization

Is referred to as housekeeping

Is a means to identify and maintain an
orderly environment

Is a prerequisite for inventory management

Prevents errors and contamination

Basic concepts: simplification, organization,
discipline, cleanliness, participation
Six (6) S’s

Seiri – organization

Seiton –tidiness

Seiso –purity

Seiketsu – cleanliness

Shitsuke – discipline

Shikkari-yarou – let’s try hard
Setup Time

Internal versus external setup time (setup time
when the machine is not running)

Reduce the setup time by studying:
• The machine itself
• Attachments
• Tools
• Workplace organization
• Transfer of internal setup to external setup
Maintenance





Focus on preventive maintenance
Develop a total productive maintenance
system (TPM)
Train and assign workers to carry out
preventive maintenance on their machines
Provide technical assistance for workers
Develop a set of measurements for
improving the maintenance system
Flexibility

Mobility

Variable output rate

Multipurpose

Flexible capability

Simplicity

Surge capacity
Transportation Strategies

Repetitive schedules

Mixed loads

Milk run

Freight consolidation

Local warehouses

Local suppliers
Implication of JIT in Repetitive
Systems

Use production rates instead of work orders

Gross-only explosions for MRP

No lead-time offset is required

Cumulative MRP format may be used

No need for due dates on individual lots

Planning buckets are usually in days or
weeks
Implications of JIT in Job Shop

Visual control of queues

The level of BOM is reduced

Manage the total load of the shop

Use rate-based scheduling

Use mixed-model scheduling

Use cellular layout

Emphasis part standardization
JIT in Purchasing

Basics:
• Scheduling system producing reasonably certain
•
•
•
•

requirements.
Achieving a stable schedule.
Pursuing all JIT objectives and building blocks.
Pruning the number of vendors.
Controlling the cost of transportation.
Lessons
• Don’t shift inventory-holding from the company to the
•
vendor.
Effectively manage vendor relationships.
Implication of JIT in Human
Resources Management

Employee involvement and empowerment

Motivation

Suggestion systems

Intra- and inter-functional teams

Job design

Compensation and rewards

Education and training

Relationships with unions
Changing Roles and
Responsibilities - Management

Culture change – from maintain status
quo to improvement

Supervisors as coaches

Treat employees fairly

Sharing information

Provide support and motivation

Provide extra time for improvement
Changing Roles and
Responsibilities - Employees

Make decisions and solve problems

Help make improvement

Work with colleagues closely

Expanded job responsibilities

Responsibility at the source

Use scientific techniques
Concluding Principles




Stabilizing and in some cases leveling the production
schedules are prerequisites to effective JIT systems.
Achieving very short lead times supports better
customer service and responsiveness.
Reducing hidden factory costs can be at least as
important as reducing costs more usually attributed to
factory operations.
Implementing the whole person concept reduces
distinctions between white- and blue-collar workers
and taps all persons’ skills for improving performance.
Concluding Principles



Cost accounting and performance measurements
need to reflect the shift in emphasis away from
direct labor as the primary source of value added.
To achieve JIT’s benefits in nonrepetitive
applications, some basic features of repetitivebased JIT must be modified.
JIT is not incompatible with MRP-based systems.
Firms can evolve toward JIT from MRP-based
systems, adopting JIT as much as or little as they
want, with an incremental approach.
Homework Assignment

Problem 3.2 and 3.12

Due Tuesday, December 3