Agenda
TPPE37 Manufacturing Control
• • • •
Lecture 8 JIT and lean production
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The first battle
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Japanese manufacturing strategies
In In1978 1978H-D H-Dtried triedtotoprove proveinincourt courtthat thattheir theirJapanese Japanese competitors competitorswere weredumping dumpingtheir theirproducts productson onthe theamerican americanmarket. market.
•• Aims Aimsat atsimplicity simplicity •• Objective: Objective:To Toeliminate eliminatewaste waste
•• Invest. Invest.showed showedthat thatthe theJap. Jap.compet. compet.costs costswere were30% 30%lower lower •• Action: Action: –– In In1981 1981H-D H-Dcopied copiedthe thethree threemost mostcommon commonapproaches approachesthe the Japanese Japanesemanufacturers manufacturersemployed employedinintheir theircost costefficient efficientmanufact. manufact. •• •• ••
JIT-philosophy Techniques to support JIT Kanban control A case study in GE
•• Productivity, Productivity,formalised formalisedas asJust Justin inTime Time(JIT). (JIT). •• Quality, Quality,continuous continuousimprovement(Kaizen), improvement(Kaizen), formalised as Total Quality formalised as Total QualityControl Control(TQC). (TQC).
Quality Qualitycircles circles Statistical Statisticalprocess processcontrol control Kanban Kanbancontrolled controlledmanufacturing manufacturing
•• Results: Results: –– –– –– © Ou Tang
Reduced Reducedinventories inventoriesby by40% 40% Increased productivity Increased productivity(MC (MCper peremployee) employee)of of129% 129% 30% fewer suppliers 30% fewer suppliers 3
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JIT and Lean Management
Minimizing Waste: Just-In-Time Production WHAT IT IS
• JIT can be divided into two terms: “Big JIT” and “Little JIT” • Big JIT (also called Lean Management) is a philosophy of operations management that seeks to eliminate waste in all aspects of a firm’s production activities • Little JIT focuses more narrowly on scheduling goods inventory and providing service resources where and when needed
• Management philosophy • “Pull” system though the plant
WHAT IT REQUIRES
• Employee participation • • • • © Ou Tang
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Industrial engineering/basics Continuing improvement Total quality control Small lot sizes © Ou Tang
WHAT IT DOES • Attacks waste • Exposes problems and bottlenecks • Achieves streamlined production
WHAT IT ASSUMES
• Stable environment
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Minimizing Waste: Focused Factory Networks
Waste in Operations 1. Waste from overproduction
These Theseare aresmall smallspecialized specializedplants plants that limit the range that limit the rangeof ofproducts products produced produced(sometimes (sometimesonly onlyone onetype type of product for an entire facility) of product for an entire facility)
2. Waste of waiting time 3. Transportation waste 4. Inventory waste Coordination
5. Processing waste
System Integration
6. Waste of motion 7. Waste from product defects © Ou Tang
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Some Someplants plantsin in Japan have Japan haveas asfew fewas as 30 and as many 30 and as manyas as 1000 1000employees employees
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Minimizing Waste: Group Technology (Part 1) •• Using UsingDepartmental DepartmentalSpecialization Specializationfor forplant plantlayout layoutcan cancause causeaalot lotofofunnecessary unnecessary material movement material movement
Saw
Saw
Saw
Grinder
Minimizing Waste: Group Technology (Part 2) •• Revising Revisingby byusing usingGroup GroupTechnology TechnologyCells Cellscan canreduce reducemovement movementand andimprove improveproduct productflow flow
Grinder
Grinder Saw
1
2
Lathe
Lathe
Press
Lathe
Press
Heat Treat
Heat Treat Grinder
Lathe
Lathe
Lathe
Press
Press
Press
Note Notehow howthe theflow flowlines linesare aregoing goingback backand andforth forth
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Saw
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Minimizing Waste: Uniform Plant Loading (heijunka)
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Minimizing Waste: Inventory Hides Problems
Machine downtime Scrap
Jan. Units
Feb. Units
Mar. Units
Total
1,200
3,500
4,300
9,000
Work in process queues (banks)
or Uniform
Jan. Units
Feb. Units
Mar. Units
Total
3,000
3,000
3,000
9,000
Paperwork backlog
How Howdoes doesthe theuniform uniformloading loadinghelp helpsave savelabor laborcosts? costs? © Ou Tang
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B
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We operate a production plant. The schedule of production could be accomplished using one of the schedules below.
Not uniform
A
Lathe
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Vendor delinquencies
Engineering design redundancies
Inspection backlogs
Change orders
Example: By identifying defective items from a vendor early in the production process the downstream work is saved
Design backlogs
Decision backlogs
Example: By identifying defective work by employees upstream, the downstream work is saved 12
The just-in-time approach
JIT philosophical approach to manufacturing
Techniques for designing and planning the JIT manufacturing system
Techniques for control of the shop floor in a JIT system
Techiques in JIT
1. 1. 2. 2. 3. 3. 4. 4. 5. 5. 6. 6.
JIT approach: ♦ zero defects ♦ zero set-up time ♦ zero inventories ♦ zero breakdowns ♦ zero lead time ♦ lot size of one
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Smooth Smooth production production Setup Setup time time reduction reduction Automation Automation Flow Flow group group Continuoue Continuoue improving improving Material Material requirements requirements
SMED SMED Poka-Yoke Poka-Yoke U-line U-line Kaizen Kaizen Kanban Kanban
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Smoothing production
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Production smoothing
•• To To utilise utilise the the resource resource more more effectively effectively •• To To elimitate elimitate unblance unblance and and create create aa synchronised synchronised and and balance balance productin productin flow. flow.
Phase Phase1: 1:Production Productionsmoothing smoothingadapting adaptingto tomonthly monthly demand changes. demand changes. ••Satblise Satblisemaster masterschedule schedule
•• Improving Improving areas: areas: Master Master production production shedule shedule and and final final assembly assembly schedule schedule
Phase Phase2: 2:Production Productionsmoothing smoothingadapting adaptingto todaily daily production dispatch production dispatch •• Mixed-model Mixed-modelassembly assembly
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Smoothing production 3 separate lines
Traditional:
Mixed model assembly
Component 1
D = (2,3,5)
1 line with setups
Component 2 Final assembly (FP1, FP2, FP3) Component 3
JIT/TQC:
Component 4
1 line with smooth production ”without” setups
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Mixed model assembly
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Setup time reduction - SMED
Requirement of component 3 •• SMED SMED -- Single Single Minute Minute Exchange Exchange of of Die Die –– Setup Setuptime timeisisshoter shoterthan than10 10minutes minutes
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⎧⎪ min ⎨ D K , i = i ⎪⎩
6
β
⎡
j =1
⎣
∑ ⎢K
⎤ − ( X j , K − 1 + b i , j )⎥ Q ⎦
Nj
2
⎫⎪ ⎬ ∀K ⎪⎭
–– Planning Planning –– Investment Investment –– Education Education
4 1 .5 1
2
Komponent 3 Ideal
•• Three Three steps steps to to achieve achieve SMED SMED distinguish distinguishexternal externaland andinternal internalsetup setuptimes times fixture, jiggar fixture, jiggar more moreoperater, operater,new newtechnology technology
0 .5 0
0
1
0
1
2
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3
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Single Dandori approach in Mitsubishi
Reducing setup time – a case study Robot
Preset Setup time
Use your imagination
preparation
Let’s break it down into ...
clean up
Preset push
Actual setup
work together
Downtime
Actual setup
Fixtures
outward
Revolving fixture table
Preset A. setup
