PULL / JIT
LT6 Training Module
INTRODUCTION
INTRODUCTION
What are Pull & JIT?
» An inventory strategy
» Improves the return on investment of a
business by…
– Reducing in-process inventory
– Reducing cycle time
» Driven by signals, or Kanban, to…
– Make the next part, or
– Move the next part
PULL/JIT| LT6 Training Module
HISTORY
» First used by the Ford Motor Company (early
1900’s)
– "dock to factory floor" – not stored in
warehouse, on factory floor
» Adopted by Toyota as part of its Toyota
Production System (TPS)
» Little space for inventory
» Required shortening Set Up Times, through
SMED
» Changed assumptions about Economic Lot
Quantity (ELQ)
» ELQ fell to 1 unit
» When a part disappeared, a signal to
produce or order a replacement.
PULL/JIT| LT6 Training Module
WHY JIT & PULL
JIT AND PULL, related to……
PULL/JIT| LT6 Training Module
WHY JIT & PULL
But why is it important?
8 Wastes
Defects
Overproduction
Waiting
Non-utilized talent
Transportation
Inventory
Motion
Extra processing
PULL/JIT| LT6 Training Module
Why Inventory?
So…
What’s So Bad About
Inventory?
PULL/JIT| LT6 Training Module
Why Inventory?
What’s So Bad About Inventory?
Work in process inventory level
(hides problems)
Unreliable
Vendors
Poor
Quality
Capacity
Imbalances
It HIDES problems
PULL/JIT| LT6 Training Module
Why Inventory?
What’s So Bad About Inventory?
Lower Inventory level to expose problems, then…
» Work on problems by:
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Reducing variability
Eliminating waste
Streamlining production and material flows
Accurate information
Unreliable
Vendors
Scrap
WIP
Capacity
Imbalances
PULL/JIT| LT6 Training Module
JIT
So, Pull & JIT are……?
» A management philosophy of continuous
and forced problem solving
» Supplies and components are ‘pulled’
through system to arrive where they are
needed when they are needed
» Goal: Achieve the minimal level of
resources required to add the necessary
value in the production system.
» A means of making WASTE easy to see.
PULL/JIT| LT6 Training Module
JIT
JIT Philosophy……
» JIT means the right quantity at the right
place and the right time.
» Minimize or eliminate wastes (hidden
rocks)
» Simpler is better
» Focuses on improving all operations
» Flexibility to produce different
models/features with minimal set up
PULL/JIT| LT6 Training Module
JIT
JIT Elements……
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Inventory reduction - exposes problems
Kanbans & pull production systems
Small lots & quick setups
Uniform plant loading (leveling the load)
Flexible resources
Efficient facility layouts
PULL/JIT| LT6 Training Module
JIT
JIT Objectives……
» To eliminate waste, by…..
– Producing the needed item
– at the right time
– and the exact quantity
AND….
– When a problem is identified, fixing it
PULL/JIT| LT6 Training Module
JIT
JIT Principles……
» Produce only what the customer wants
» Produce only at the rate the customer
wants
» Produce with perfect quality
» Produce with minimum lead time
» Produce with no waste of labor, material
or equipment
» Produce with
“flow”
PULL/JIT| LT6 Training Module
Flow
What is Flow?
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One piece at a time, opposite of batching
Minimal distance between operations
Small flexible equipment VS Large inflexible
Cross Functional VS Departmentalized
Cross Trained operators, easily moved
Produce to the Takt,
Level Loaded production
PULL/JIT| LT6 Training Module
Enablers
What ENABLES JIT to work
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Quick set ups (SMED)
Stable processes
Use of standard containers
Doable stable schedules with adequate visibility
TAKT-Time
5-S efforts
Kaizen Events
Visual controls
Flexible workers
Tools at the point of need
Products designed for manufacturing
Group Technology (product families)
Total Productive Maintenance
Kanban
PULL/JIT| LT6 Training Module
Benefits
What kind of benefits can you expect with JIT?
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Smaller inventories
Shorter lead times
Quicker response to customer demand
Improved quality
Reduced space requirements
Lower production costs
Increased productivity
Greater flexibility
Lower inventory carry costs (%25)
PULL/JIT| LT6 Training Module
Works Best
JIT works best when….
» Trust is present
– labor/management
– suppliers/consumers
» Individuals are familiar with problem solving
» Quality at the source is emphasized
» There is agreement over value and waste
» Applied in the growth to maturity phases of Product Life Cycle
» Products are somewhat “standard”
» Standard/fixed pay-rate
– Problems with piece-rate systems
» Universal agreement that change is needed
PULL/JIT| LT6 Training Module
Key Enablers…
Quality at the Source
» For JIT to work, quality must be high
– There should be no extra inventory to buffer against the
production or use of defective units
» Producing poor-quality items, and reworking or rejecting
them is wasteful
» The workers must be responsible for inspection &
production quality
» The philosophy is, “NEVER pass along a defective item
PULL/JIT| LT6 Training Module
Key Enablers…
One Piece Flow, Continuous Flow
» The opposite of batch, lot, or mass processing
» Product should move (flow) from operation to operation,
only when it is needed, in the smallest increment
possible
» One piece is the ultimate (single-piece-flow)
» Cross train operators
» Operators float to the bottleneck
PULL/JIT| LT6 Training Module
Key Enablers…
Pull Production, an feature of JIT
» Actual customer demand drives the manufacturing
process
» It creates a system of cascading production and delivery
signals from downstream demand to upstream
production in which nothing is produced by the upstream
supplier until the downstream customer signals a need
– Big Benefit – Schedule only one point the value stream
» The rate of production for each product is equal to the
rate of customer consumption
PULL/JIT| LT6 Training Module
Key Enablers…
Pull Example
Production
Schedule
Customer
Request
Leveled
Schedule
A
C
A
B
A
Fab
Vendor
Fab
Vendor
Fab
Vendor
Fab
Vendor
Sub
Final Assy
Sub
PULL/JIT| LT6 Training Module
Key Enablers…
Work Balancing / TAKT Time
» Work balancing maximizes operator efficiency by matching
work content to TAKT time
» TAKT time is the rate at which customers require your product
» TAKT time is calculated as follows:
Available work time per day
Daily required customer demand in parts per day
PULL/JIT| LT6 Training Module
Simulation…
Let’s see how this works
» YESCO Aviation – Brand new operation
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Building planes
4 Assembly Operators
1 Material Delivery
1 Timer
1 Customer
1 Manager
PULL/JIT| LT6 Training Module
Simulation…
Let’s see how this works
» YESCO Aviation – Brand new operation
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Customer watches for defects
Building and moving 3 at a time (ELQ)
Call Mtl Handler to move product
Customer will take all you can build
Don’t change layout
Colored paper will track “Lead Time”
Will run until enough work in process to capture data
PULL/JIT| LT6 Training Module
Simulation…
Let’s see how this works
» YESCO Aviation – How’d we do?
Run #1 Run # 2
Lot Size
WIP
Lead Time
Total Run Time
Deiveries
# of People
Space
Productivity
Defectives
Diff
7.25
18
6
1.65
10
5
0.23
56%
83%
0.41
1.21
2.93
PULL/JIT| LT6 Training Module
Simulation…
Let’s see how this works
» YESCO Aviation – Run # 2
– Move however you like
– Lot Size – 1
– Introduce Single Piece Flow discipline
» How’d we do
» Wrap up
PULL/JIT| LT6 Training Module
Conclusion
What’s next?
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Ensure quality
Remove clutter & minimize storage
Reduce setup times
Level load orders, produce to takt
Implement layout changes
– Cellular manufacturing &/or close proximity
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Cross train and teach to float to the bottleneck
Move to pull production
Extend methods to suppliers
Review and improve
PULL/JIT| LT6 Training Module
Conclusion
Q&A
PULL/JIT| LT6 Training Module