Just-In-Time
-
Upload
raj-shravanthi -
Category
Education
-
view
150 -
download
0
Transcript of Just-In-Time
Presentation by-A.RAJ SHRAVANTHI
INTRODUCTIONAlso called Lean production or stockless production
JUST-IN-TIME/JIT is an approach which seeks to eliminate all sources of waste, anything which doesn’t add value in production activities, by providing the right part at the right place at the right time . just as they are needed!
Just-in-time manufacturing is a way of managing manufacturing systems that could reduce waste, and lower cost, thus increasing profit.
JIT- production is based on demand
History(1970) The realization for the new system came after
World War II when the Japanese automotive manufactures knew they were far behind the American motor companies.
JIT manufacturing is a result of limited demand, space, and resources in Japan compared to America.
Toyota Motor Company-( Birthplace of the JIT) Taiichi Ohno came up with a system that would
better fit Japan's capabilities. JIT is now on the rise in American Industries.
Taiichi Ohno, Toyota officials in the 50s, known as FATHER OF JIT
JIT Goals and Building Blocks
Product Design
ProcessDesign
PersonnelElements
Manufactur-ing Planning
Eliminate disruptionsMake the system flexible
Reduce setupand lead times
Eliminate wasteMinimize inventories
Abalancedrapid flow
UltimateGoal
SupportingGoals
BuildingBlocks
JIT Building Blocks 1. Product design 2. Process design 3. Personnel/organizational
elements 4. Manufacturing
planning and control
1. Product Design Standard parts Modular design Quality
Poke-Yoke (Fail Safe) Design Change the process or resources Try to eliminate reliance on human
experience and knowledge Examples:
Color-coded parts Templates Use of counters on operations Design plugs to only be inserted one
way
2. Process Design Small lot sizes Setup time reduction Manufacturing cells Limited work in process Quality improvement Production flexibility Little inventory storage
Benefits of Small Lot Sizes
Reduces inventory
Less storage spaceLess rework
Problems are more apparent
Increases product flexibilityEasier to balance operations
Production Flexibility Reduce downtime by reducing
changeover time Use preventive maintenance to
reduce breakdowns Cross-train workers to help clear
bottlenecks Reserve capacity for important
customers
3. Personnel/Organizational Elements Workers as assets Cross-trained
workers Continuous
improvement Cost accounting Leadership/project
management
4. Manufacturing Planning and Control
Pull systems Visual systems Close vendor relationships Reduced transaction processing Preventive maintenance
JIT PurchasingLong-termLong-term
contracts withcontracts withsuppliers.suppliers.
Only a fewOnly a fewsuppliers.suppliers.
Parts deliveredParts deliveredin small lots.in small lots.
MinimalMinimalinspection ofinspection of
materials.materials.
GroupedGroupedpayments topayments to
vendor.vendor.
Pull/Push Systems
Pull system: System for moving work where a workstation pulls output from the preceding station as needed. (e.g. Kanban)
Push system: System for moving work where output is pushed to the next station as it is completed(eg:MRP)
Pre-JIT: Traditional Mass Production
Big lot sizesLots of inventory”PUSH” material to nextstage
Lowerper unit
cost
Big purchase shipments
Big “pushes” of finished goodsto warehouses or customers
???
16
Post-JIT: “Lean Production”
Smaller lotsFaster setupsLess inventory, storage space”PULL” material to next stage
Minimalor no
inventoryholding
cost
Smaller shipments
Goods are pulled out ofplant by customer demand
17
Tighter coordination along the supply chainGoods are pulled along
— only make and ship what is needed
Examples of Visual Controls 5S-CANDO (arranging) Jidoka or autonomation
Andon lights and buzzers announce tool status.
kanban squares, cards, containers. Lines on the floor to mark reorder points
Safety: colored labels for materials Statistical process control charts:
should be clearly visible.
5S-CANDO 5S-CANDO, a systematic approach to cleaning
and organizing the workplace, suppresses friction.
Seiri = Clearing up "When in doubt, throw it out."
Seitori = Organizing (Arranging) "A place for everything and everything in its place."
Seiso = Cleaning (Neatness) Shitsuke = Discipline Seiketsu = Standardization (Ongoing
improvement, holding the gains)
Kanban System( Kan=card, Ban= signal )
Kanban is the Japanese word meaning “signal” or “visible record”
Card or other device that communicates demand for work or materials from the preceding station
Paperless production control system Authority to pull, or produce comes
from a downstream process.
Kanban ExampleWorkcenter A Workcenter B
Workcenter B uses parts produced by Workcenter A
How can we control the flow of materials so that B alwayshas parts and A doesn’t overproduce?
Kanban card: Signal to produceWorkcenter A Workcenter B
Kanban Card
When a container is opened by Workcenter B, its kanban card is removed and sent back to Workcenter A.This is a signal to Workcenter A to produce another box of parts.
Empty Box: Signal to pullWorkcenter A Workcenter B
Empty box sent back. Signal to pull another full box intoWorkcenter B.Question: How many kanban cards here? Why?
Kanban No.Kanban No. 5678990 5678990 part No: part No: 66789X66789Xdescription description 16ga. 16ga.
Copper WireCopper Wireunits units Ft.Ft.reorder/lot qty reorder/lot qty 2020store location store location Row 12, Bin Row 12, Bin
66supplier supplier BICCBICCsupplier telsupplier tel 0208-891-0208-891-
01210121supplier part supplier part RT45502RT45502routing processName/location of next procesName/location of preceding
processcontainer type & capacitynumber of containers
released
What does a Kanban card look like?
Customer
Supplier
Supplier
Supplier
Supplier
Final Assembly
Fabric
Fabric
Fabric
Fabric Subass
Subass
Call (Kanban) & Pull
Call (Kanban) & PullCall (Kanban) & Pull
Summary JIT Goals and Building Blocks
Product Design
ProcessDesign
PersonnelElements
Manufactur-ing Planning
Eliminate disruptionsMake the system flexible
Reduce setupand lead times
Eliminate wasteMinimize inventories
Abalancedrapid flow
UltimateGoal
SupportingGoals
BuildingBlocks
(Work toward flexibility)Process flexibilityMachine flexibilityOperator flexibilityQuick changeover with short setup times
JIT goals Flexible enterprise; Only produce products
needed; Reducing the inventory in
process, finished goods and raw
materials; Reduce costs of
manufacturing; Creating space in the factory; Minor "lead time" in
manufacturing; Better customer service; Less waste; Greater return on investment.
The purpose of lean is to remove all forms of waste from the value stream.
Waste is ‘anything other than the minimum amount of equipment, materials, parts, space, and worker’s time, which are absolutely essential to add value to the product. — Shoichiro (Toyoda President,Toyota)
Understanding of friction, waste, or muda is the foundation of the lean Manufacturing. A job can consist of 75 percent waste (or even more).
The chief obstacle is the fact that waste often hides in plain sight
The role of inventory in traditional and JIT systems: The water and the rocks metaphor
Material quality problems Long
setups
Poor training Break
downs
Material handling
Traditional systems use inventory (water) to buffer the process from problems (rocks) that cause disruption.
Water = Inventory
The role of inventory in traditional and JIT systems: The water and the rocks metaphor
Material quality problems
Long setups
Poor training Break
downs
Material handling
JIT systems view inventory as waste and work to lower inventory levels to expose and correct the problems (rocks) that cause disruption.
The role of inventory in traditional and JIT systems: The water and the rocks metaphor
Material quality problems Long
setups
Poor training Break
downs
Material handling
Lowering the level of inventory is relatively easy to do. However, the problems that arise must be corrected quickly … Otherwise, without decoupling inventory, the process will flounder.
Material Waste Hides in Plain Sight
CleaningTank 1
CleaningTank 2
Dirty parts Clean parts
CleanWater
Discard water
CleanWater
The parts get clean, so no one questions this. What is wrong with this picture?
Why Not Make the Water Work Twice?
CleaningTank 1
CleaningTank 2
Dirty parts Clean parts
Discard water
CleanWater
The almost clean water from the second tank is good enough for use in the first tank. Water usage can be cut 50 percent.
Forms of Waste:
Overproduction Waiting time Transportation Processing Inventory Motion Product Defects
Recognize the Waste
This principle has been stressed by: Henry Ford Taiichi Ohno (Toyota production
system) Tom Peters (Thriving On Chaos) Shigeo Shingo J. F. Halpin (Zero Defects)
TPS Definitions of Waste1. Overproduction2. Waiting, including time in queue3. Transportation (between workstations, or
between supplier and customer)4. Non-value-adding activities5. Inventory6. Waste motion7. Cost of poor quality: scrap, rework, and
inspection
SEVEN WASTESJIT ALWAYS INSISTED ON ELIMINATION OF WASTES.SHIGCO SHINGO, A JAPANESE JIT AUTHORITY IDENTIFIES 7 WASTES. TO HIM BY ATTENDING TO THESE WASTE, THE IMPROVEMENT IS ACHIEVED. THOSE 7 KINDS OF WASTAGES ARE:
1.Waste of stocks.2.Waste of waiting.3.Waste of processing.4.Waste of defective production.5.Waste of over production.6.Waste of motion.7.Waste of transportation.
Summary JIT Goals and Building Blocks
Product Design
ProcessDesign
PersonnelElements
Manufactur-ing Planning
Eliminate disruptionsMake the system flexible
Reduce setupand lead times
Eliminate wasteMinimize inventories
Abalancedrapid flow
UltimateGoal
SupportingGoals
BuildingBlocks
Setup Reduction
Setup reduction is the process of reducing the time required to convert from production of the last good piece of unit A to the first good piece of unit B.
use methods engineering/common sense.
Ideal lot size = 1.
Setup Reduction (Cont.)
Setup activities: External: Operations performed while
the machine is running. Internal: Operations performed after the
machine is stopped.
Setup…responsibility of the operator.
Continuous Flow Production
Flow with JIT
Traditional Flow
CustomersSuppliers
Customers
Suppliers
Production Process (stream of water)
Inventory (stagnant ponds) Material
(water in stream)
SUMMARYKey Features of the JIT Approach
Smooth, uniform production rateSmooth, uniform production rate
Pull method of productionPull method of production
Purchase is small lot sizesPurchase is small lot sizes
Quick, inexpensive setupsQuick, inexpensive setups
High quality of materialsHigh quality of materials
Effective preventive maintenanceEffective preventive maintenance
TeamworkTeamwork
Multiskilled workersMultiskilled workers
Benefits of JIT:
The main benefits of just in time manufacturing system are the following:
1.Funds that were tied up in inventories can be used elsewhere.
2.Areas previously used, to store inventories can be used for other more productive uses.
3.Throughput time is reduced, resulting in greater potential output and quicker response to customers.
4.Defect rates are reduced, resulting in less waste and greater customer satisfaction.
Disadvantages of JIT:
• JIT REQUIRES SPECIAL TRAININGS WITH REORGANISATIONS OF POLICIES AND PROCEDURE.
• RESISTANCE TO CHANGE: JIT INVOLVES A CHANGE THROUGH OUT THE WHOLE ORGANISATIONS, BUT HUMAN NATURE RESISTS CHANGE.
• JIT REQUIRES MULTI-SKILLED WORKERS WITH FLEXIBILITY TO CHANGE. AND IT IS VERY HARD TO FIND THOSE WORKERS.
•Harley Davidson •Toyota Motor Company •General Motors •Ford Motor Company •Manufacturing Magic •Hawthorne Management Consulting •Strategy Manufacturing Inc.
Converting to a JIT System Get top management commitment Decide which parts need most effort Obtain support of workers Start by trying to reduce setup times Gradually convert operations Convert suppliers to JIT Prepare for obstacles Value chain mapping
References:
Operations & supply management- Chase, Ravi Shankar….
www.justintime.com Sdgi.com www.syspro.com