JUST IN TIME PRODUCTION SYSTEM

KIOT
Lean system engineering
Target group: 3rd year GED
Chapter five
Just-in-Time Production system
“Establishing World Class Manufacturing Practices”
By: Endashaw Yohannes
Kombolcha/Ethiopia
May , 2019
5/27/2019 1

2 - 2SKB
Just-In-Time is
 A manufacturing system which produces:
 What the customer wants
 In the quantity the customer wants
 When the customer wants it
 While using the minimum:
 Raw materials
 Equipment
 Labor
 Space

2 - 3SKB
Philosophy of Just-in-Time
 JIT originated in Japan at Toyota Motor Co, fueled by a need to
survive the devastation post WWII
 JIT gained worldwide prominence in the 1970s
 Often termed “Lean Production” or “Lean Systems”
 Broad view that entire organization has the same goal - to serve
customers

2 - 4SKB
The Philosophy of JIT con’t
o JIT is built on simplicity - simpler is better
o Continuous improvement – often using kaizen blitz
o Visibility – all waste must be visible to be identified and
eliminated
o Flexibility - to adapt to changes in environment

2 - 5SKB
 Attacks waste (Any thing not adding value to the
product)
 Achieves streamlined productionn by reducing
inventory
 Exposes problems and bottlenecks caused by variability
What Does Just-in-Time Do?

Goal of JIT
The ultimate goal of JIT is a balanced system.
(Achieves a smooth, rapid flow of materials through
the system)
The supporting goals are:
 Eliminate disruptions
 Make the system flexible
 Eliminate waste, especially excess inventory

 JIT manufacturing focuses on production system to
achieve value-added manufacturing
 TQM is an integrated effort designed to improve quality
performance at every level
 Respect for people rests on the philosophy that human
resources are an essential part of JIT philosophy
8
Three Elements of JIT con’t

9
Elements of JIT Manufacturing
 Achieved by focusing on these elements:
 Inventory reduction - exposes problems
 Kanban & pull production systems
 Small lots & quick setups
 Uniform plant loading
 Flexible resources
 Efficient facility layouts

10
Role of Inventory Reduction
 Inventory = Lead Time (less is better)
 Inventory hides problems

Pull/Push Systems
 Pull system: System for moving work where a
workstation pulls output from the preceding station
just as it is needed. (e.g. Kanban)
vs.
 Push system: System for moving work where output
is pushed to the next station as it is completed

Comparison between Pull and Push
system

Advantages of Push and pull system
Pull system Push system
Limited Inventory High Inventory
Customer centric Producer centric
Improve cash flow Make -to-stock
Make -to-order Forecasting demand

Disadvantages of Push and Pull system
Pull system Push System
Balanced systems MUST be in
place
Can generate large quantities of
scrap before errors are discovered
Setup times will greatly impact
throughput
Requires maintenance of large and
complex databases
Any problem will lead to unhappy
customers
Requires diligence to maintain
effective product flow

Kanban Production Control System
 Kanban: Card or other device that communicates
demand for work or materials from the preceding
station
 Japanese word meaning “signal” or “visible record”
may be a card, or may be a flag, ball etc.
 Paperless production control system
 Kanban card indicates standard quantity of production
 Used often with fixed sized container

Kanban Production Control System
o The Kanban cards provide direct control (limit) on the
amount of work-in-process between cells.
o maintain discipline of pull production
o Signifies an authority to pull or produce which comes
from a downstream process
 Production Kanban authorizes production
 Withdrawal Kanban authorizes movement of goods

Determination of the Number of
Kanbans Needed
o Setting up a kanban system requires determining the
number of kanbans (or containers) needed.
o Each container represents the minimum production lot
size
o An accurate estimate of lead time required to produce
a container is key to determining how many kanbans
are required

Kanban Signals “Pull” Material Through
the Process
Storage
Part A
Storage
Part AMachine
Center
Assembly
Line
Material Flow
Card (signal) Flow
Withdrawa
l
kanban
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
This puts the
system back
where it was
before the item
was pulled
The process begins by the Assembly Line
people pulling Part A from Storage
Production kanban

© 2006 Prentice Hall, Inc. 16 – 21
Kanban Signals
Work
cell
Raw
Material
Supplier
Kanban
Purchased
Parts
Supplier
Sub-
assembly
Ship
Kanban
Kanban
Kanban
Kanban
Finished
goods
Customer
order
Final
assembly
Kanban

22
Small Lot Sizes & Quick Setups
 Small lots mean less average inventory and shorten manufacturing lead
time
 Small lots with shorter setup times increase flexibility to respond to
demand changes
 Strive for single digit setups- < 10 minutes
 Setup reduction process is well-documented
 External tasks- do as much preparation while present job is still
running
 Internal tasks- simplify, eliminate, shorten steps involved with
location, clamping, & adjustments
 Ultimate goal is single unit lot sizes

© Wiley 2010 23
Uniform Plant Loading
 A “level” schedule is developed so that the same mix of
products is made every day in small quantities
 Leveling the schedule can have big impact along whole supply
chain
Monday Tuesday Wednesday Thursday Friday
AAAAA BBBBB BBBBB DDDDD EEEEE
AAAAA BBBBB BBBBB CCCCC EEEEE
Monday Tuesday Wednesday Thursday Friday
AABBBB AABBBB AABBBB AABBBB AABBBB
CDEE CDEE CDEE CDEE CDEE
5 units
5 units
10 units
Weekly Production Required
Traditional Production Plan
JIT Plan with Level Scheduling
A
B
C
D
E
10 units
20 units

24
Flexible Resources
 Moveable, general purpose equipment:
 Portable equipment with plug in power/air
 Drills, lathes, printer-fax-copiers, etc.
 Capable of being setup to do many different things with minimal setup
time
 Multifunctional workers:
 Workers assume considerable responsibility
 Cross-trained to perform several different duties
 Trained to also be problem solvers

25
Effective Facility Layouts
 Workstations in close physical proximity to reduce
transport & movement
 Smooth flow of material
 Often use:
 Cellular Manufacturing (instead of process focus)
 U-shaped lines: (allows material handler to quickly drop
off materials & pick up finished work)

26
Respect for People: The Role of
Employees
 Associates gather performance data
 Team approaches used for problem-solving
 Decisions made from bottom-up
 Everyone is responsible for preventive maintenance

27
Respect for People
The Role of Employees:
 Genuine and meaningful respect for associates
 Willingness to develop cross-functional skills
 Bottom-round management – consensus management by
committees or teams
 Quality circles – small volunteer teams that solve quality
problems

28
Respect for People
Lifetime Employment:
 Everyone feels secure/is empowered
 Everyone is responsible for quality: understand
both internal and external customer needs

The Role of Management:
 Responsible for culture of mutual trust
 Serve as coaches & facilitators
 Responsible for developing workers
 Provide multi-functional training
 Facilitate teamwork
 Support culture with appropriate incentive system including
non-monetary
29
Respect for People

30
Respect for People
Supplier Relationships
 Single-source suppliers
 Can supply entire family of parts
 Build long-term relationships with small number of
suppliers
 Fewer contracts
 Cost and information sharing
 Work together to certify processes

31
JIT and TQM
 Integrate quality into all processes
 Focus on continuous improvement - Kaizen
 Quality at the source - sequential inspection
 Jidoka - authority to stop line
 Poka-yoke - fail-safe all processes
 Preventive maintenance - scheduled
 Work environment - everything in its place, a place for
everything

Benefits of JIT
o Reduced inventory
o Improved quality
o Lower costs
o Reduced space requirements
o Reduced lead times
o Increased productivity
o Greater flexibilityy
o Reduced scrap and rework
o Better relations with suppliers
o Simplified scheduling and
control activities
o Increased capacity
o Increased equipment
utilization
o Better use of human resources
o More product variety
o Reduced need for indirect
labor

33
Implementing JIT
 Starts with a company shared
vision of where it is and where it
wants to go
 Management needs to create the
right atmosphere
 Implementation needs a designated
“Champion”
 Implement the sequence of
seven steps
1. Make quality improvements
2. Reorganize workplace
3. Reduce setup times
4. Reduce lot sizes & lead times
5. Implement layout changes
6. Follow pull production sytem
7. Develop relationship with
suppliers

Summary: Just-In-Time Production
• Management philosophy
• “Pull” system though the plant
WHAT IT IS
• Employee participation
• Industrial engineering/basics
• Continuing improvement
• Total quality control
• Small lot sizes
WHAT IT REQUIRES
• Attacks waste
• Exposes problems and bottlenecks
• Achieves streamlined production
WHAT IT DOES
• Stable environment
WHAT IT ASSUMES

Comparison of JIT and Traditional Systems
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

JUST IN TIME PRODUCTION SYSTEM

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