精益生产介绍Introduction to Lean Manufacturing.ppt

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1、Introduction to Lean Manufacturing1 2009,Levinson Productivity Systems,P.C.www.ct-One Page OverviewThe purpose of lean is to remove all forms of waste from the value stream.Waste includes cycle time,labor,materials,and energy.The chief obstacle is the fact that waste often hides in plain sight,or is

2、 built into activities.2 2009,Levinson Productivity Systems,P.C.www.ct-ContentsBenefits of Lean ManufacturingThe Origins of Lean ManufacturingWhat Is Lean Manufacturing?Waste,Friction,or MudaLean Manufacturing and Green Manufacturing/ISO 14001Some Lean Manufacturing TechniquesConclusion3 2009,Levins

3、on Productivity Systems,P.C.www.ct-Benefits of Lean ManufacturingLean manufacturing delivers an insurmountable competitive advantage over competitors who dont use it effectively.4 2009,Levinson Productivity Systems,P.C.www.ct-Benefits of Lean Manufacturing(1)Lower production cost higher profits and

4、wagesCost avoidance flows directly to the bottom line.(2)Supports ISO 14001 and green manufacturingReduction of material waste and associated disposal costs higher profits(3)Shorter cycle times:make-to-order vs.make-to-stock5 2009,Levinson Productivity Systems,P.C.www.ct-Bottom Line and the Language

5、 of MoneyThe first comprehensive implementation of lean manufacturing yielded:Stock appreciation of 63 percent per year,for 16 years(not counting dividends)7.2 percent annual wage growthThe next section will discuss lean manufacturings origins.6 2009,Levinson Productivity Systems,P.C.www.ct-The Orig

6、in of Lean ManufacturingDiscussion question:Who created the Toyota Production System?7 2009,Levinson Productivity Systems,P.C.www.ct-The Creator of the Toyota Production System8 2009,Levinson Productivity Systems,P.C.www.ct-Origin of the Toyota Production SystemTaiichi Ohno said openly that he got t

7、he idea from Henry Fords books and the American supermarket.Fords My Life and Work(1922)describes just-in-time(JIT)and other lean concepts explicitly.Depletion of supermarket shelf stock triggers replenishment;it is a pull system like kanban or Drum-Buffer-Rope.9 2009,Levinson Productivity Systems,P

8、.C.www.ct-Bottom Line Results of the TPSThe Ford Motor Companys original stock grew 63%per year(not counting dividends)and 7.2%annual wage growth.Toyota recently superseded General Motors as the worlds largest automobile company.The next section will show how the TPS delivers these results.10 2009,L

9、evinson Productivity Systems,P.C.www.ct-What is Lean Manufacturing?A systematic approach to the identification and elimination all forms of waste from the value stream.11 2009,Levinson Productivity Systems,P.C.www.ct-Concept of Friction,Waste,or MudaUnderstanding of friction,waste,or muda is the fou

10、ndation of the lean Manufacturing.12 2009,Levinson Productivity Systems,P.C.www.ct-The First Step is to Recognize the WasteThis principle has been stressed by:Henry FordTaiichi Ohno(Toyota production system)Tom Peters(Thriving On Chaos)Shigeo ShingoJ.F.Halpin(Zero Defects)13 2009,Levinson Productivi

11、ty Systems,P.C.www.ct-Waste Often Hides in Plain ViewWe cannot eliminate the waste of material,labor,or other resources until we recognize it as waste.A job can consist of 75 percent waste(or even more).Classic example:brick laying in the late 19th century14 2009,Levinson Productivity Systems,P.C.ww

12、w.ct-Waste is Often Built Into JobsPre-Gilbreth Bricklaying15 2009,Levinson Productivity Systems,P.C.www.ct-This is a Real ExampleTop:The usual method of providing the bricklayer with material(Gilbreth,Motion Study,1911).Bottom:Nonstooping scaffold designed so that uprights are out of the bricklayer

13、s way whenever reaching for brick and mortar at the same time.16 2009,Levinson Productivity Systems,P.C.www.ct-Post-Gilbreth Brick LayingThe solution is obvious(in retrospect),but first we have to know that we have a problem!17 2009,Levinson Productivity Systems,P.C.www.ct-Another Example:Fabric Fol

14、dingRedesign of this job to eliminate the need to walk doubled its productivity.We will see that material waste also hides in plain sight.18 2009,Levinson Productivity Systems,P.C.www.ct-Material Waste Hides in Plain SightCleaningTank 1CleaningTank 2Dirty partsClean partsCleanWaterDiscard waterClean

15、WaterThe parts get clean,so no one questions this.What is wrong with this picture?19 2009,Levinson Productivity Systems,P.C.www.ct-Why Not Make the Water Work Twice?CleaningTank 1CleaningTank 2Dirty partsClean partsDiscard waterCleanWaterThe almost clean water from the second tank is good enough for

16、 use in the first tank.Water usage can be cut 50 percent.20 2009,Levinson Productivity Systems,P.C.www.ct-Spin Coating of Semiconductor WafersThe product is the coated wafer,and the job has always been done this way in the semiconductor industry.This is how waste hides in plain view.21 2009,Levinson

17、 Productivity Systems,P.C.www.ct-Lessons so farWaste often hides in plain view.People become used to living with it or working around it.Definition for employees at all levels:If its frustrating,a chronic annoyance,or a chronic inefficiency,its friction.(Levinson and Tumbelty,1997,SPC Essentials and

18、 Productivity Improvement,ASQ Quality Press)22 2009,Levinson Productivity Systems,P.C.www.ct-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

19、 poor quality:scrap,rework,and inspection23 2009,Levinson Productivity Systems,P.C.www.ct-Waste(notes page)24 2009,Levinson Productivity Systems,P.C.www.ct-Waiting as a Form of WasteOf the total cycle time or lead time,how much involves value-adding work?How much consists of waiting?25 2009,Levinson

20、 Productivity Systems,P.C.www.ct-The Value-Adding Bang!Masaaki Imai uses Bang!to illustrate that the value-adding moment may consist of a literal Bang!Contact between tool and workContact between golf club and ball26 2009,Levinson Productivity Systems,P.C.www.ct-Imais Golf AnalogyIn a four hour golf

21、 game,the golf club is in contact with the ball for less than two seconds.The same proportion of value-adding to non-value-adding time prevails in many factories.Additional analogies:Waiting for other players=waiting for toolsWalking=transportationSelecting a club and addressing the ball=setup27 200

22、9,Levinson Productivity Systems,P.C.www.ct-The Value-Adding Bang,ContinuedIn a factory,the value-adding Bang!takes place when,for example,a stamping machine makes contact with the part.All other time,such as waiting,transportation,and setup,is non-value-adding.The proportion of value-adding to non-v

23、alue-adding time may in fact be similar to that in a typical golf game!28 2009,Levinson Productivity Systems,P.C.www.ct-Cycle Time AccountingThe basic idea is to attach a stopwatch to each job(or sample jobs)to determine exactly how the work spends its time.In practice,the production control system

24、should handle this.The Gantt Chart may be modified to display the times by category.29 2009,Levinson Productivity Systems,P.C.www.ct-Cycle Time Accounting,ContinuedThe clock starts the instant a job begins an activity and stops the instant it ends.If the work waits for a tool or operator,this is a d

25、elay and not processing.When work is gated out of an operation,it usually waits for transportation(delay)or is in transit(transportation).Placement of the work in the tool is handling,not processing.30 2009,Levinson Productivity Systems,P.C.www.ct-Gantt Chart ModificationOnly machining is value-addi

26、ng time.This Gantt format of the cycle time makes non-value-adding time highly visible.31 2009,Levinson Productivity Systems,P.C.www.ct-Waste:SummaryThis section has shown how wastes of material,labor,and cycle time can hide in plain view.Cycle time reduction can yield decisive competitive advantage

27、s,including make to order as opposed to make to forecast.The next section will cover Green manufacturing.32 2009,Levinson Productivity Systems,P.C.www.ct-Green is the Color of Moneywe will not so lightly waste material simply because we can reclaim itfor salvage involves labour.The ideal is to have

28、nothing to salvage.Henry Ford,Today and Tomorrow 33 2009,Levinson Productivity Systems,P.C.www.ct-The Birth of Green ManufacturingHenry Ford could probably have met ISO 14001 requirements in an era when he could have legally thrown into the river whatever wouldnt go up the smokestack.He perfected ne

29、w processesthe very smoke which had once poured from his chimneys was now made into automobile parts.Upton Sinclair,The Flivver King34 2009,Levinson Productivity Systems,P.C.www.ct-Fords Green ManufacturingRecovery and reuse of solventsDistillation of waste wood for chemicals yielded enough money to

30、 pay 2000 workers.Kingsford charcoalDesign of parts and processes to minimize machining wasteReuse of packaging materialsSlag paving materials and cement35 2009,Levinson Productivity Systems,P.C.www.ct-Identification of Material and Energy WastesMaterial and energy waste can easily be built into a j

31、ob.Elimination of these wastes is central to green manufacturing and the ISO 14001 standard and,more importantly,very profitable.We cannot,however,remove this waste before we identify it.36 2009,Levinson Productivity Systems,P.C.www.ct-Control Surface ApproachThe material and energy balance isstanda

32、rd practice for chemical processdesign.Outputs must equal inputs.Material outputs,for example,include everything that is thrown away,as well as the product.37 2009,Levinson Productivity Systems,P.C.www.ct-ProcessControl SurfaceExample:Spin Coating of Semiconductor WafersThe control surface analysis

33、forces the waste to become visible,and causes people to ask if there is a practical way to avoid it.Wafers andPhotoresistPhotoresistCoatedWafers38 2009,Levinson Productivity Systems,P.C.www.ct-ProcessControl SurfaceExample:MachiningThe waste that is usually taken for granted(metal chips and used cut

34、ting fluid)suggests product or process redesign to reduce machining.Metal billetsand cuttingfluidMetal turningsand cuttingfluidProduct39 2009,Levinson Productivity Systems,P.C.www.ct-Discussion QuestionDo you know of processes in which materials are thrown away(or recycled)?If so,can the process or

35、product be redesigned to reduce the waste?Could the discarded materials be reused or recycled in some manner?Can energy-intensive processes be made more efficient?40 2009,Levinson Productivity Systems,P.C.www.ct-Lean Manufacturing TechniquesSome principles and activities for lean manufacturing41 200

36、9,Levinson Productivity Systems,P.C.www.ct-Design for ManufactureSynergistic with ISO 9000:2000 7.3,Design Control.Involve manufacturing,customers,and other related departments in the design process.Dont throw the design over the wall to manufacturing.The design must be manufacturable by the equipme

37、nt in the factory.Process capability:Design for Six Sigma42 2009,Levinson Productivity Systems,P.C.www.ct-5S-CANDO5S-CANDO,a systematic approach to cleaning and organizing the workplace,suppresses friction.Seiri=Clearing upWhen in doubt,throw it out.Seitori=Organizing(Arranging)A place for everythin

38、g and everything in its place.Seiso=Cleaning(Neatness)Shitsuke=DisciplineSeiketsu=Standardization(Ongoing improvement,holding the gains)43 2009,Levinson Productivity Systems,P.C.www.ct-Visual ControlsBasically,the intent is to make the status of the operation clearly visible to anyone observing that

39、 operation(Wayne Smith,1998).Visual controls are like a nervous system(Suzaki,1987)Visual controls identify waste,abnormalities,or departures from standards(Caravaggio,in Levinson,1998)44 2009,Levinson Productivity Systems,P.C.www.ct-Examples of Visual Controls5S-CANDO(arranging)Jidoka or autonomati

40、onAndon lights and buzzers announce tool status.JIT:kanban squares,cards,containers.Lines on the floor to mark reorder pointsSafety:colored labels for materialsStatistical process control charts:should be clearly visible.45 2009,Levinson Productivity Systems,P.C.www.ct-Visible ManagementA visible pr

41、oduction management system should indicate:(1)What the operation is trying to makeMeasure the takt rate,or desired production per unit time.(2)What the operation is achieving(3)What problems hinder the production goal?American workplaces used such controls prior to 1911.46 2009,Levinson Productivity

42、 Systems,P.C.www.ct-Pull Production Control SystemsJust-In-Time(JIT)First described by Henry Ford in My Life and Work(1922)KanbanDrum-Buffer-Rope(Goldratt)All reduce inventory and its carrying costs,along with cycle time.Tie-in with small lot and single unit processing47 2009,Levinson Productivity S

43、ystems,P.C.www.ct-Drawbacks of Batch ProcessingRunning equipment(e.g.a heat treatment furnace)at less than full load wastes capacity.Waiting for a full load wastes time.Waste of capacity is not a problem except at a constraint operation(Goldratts Theory of Constraints).Batches introduce waiting time

44、 when they arrive at single-unit tools en masse.Batch-and-queue forces extra cycle time(waiting)into the operation.48 2009,Levinson Productivity Systems,P.C.www.ct-Single-Unit Processing Reduces Cycle TimeWayne Smith(1998)defines manufacturing cycle efficiency as(Value-adding time)(Total cycle time)

45、This is often less than 1 percent.Remember Masaaki Imais value-adding Bang!conceptGolf analogy:the club head is in contact with the ball for less than two seconds in a typical game.49 2009,Levinson Productivity Systems,P.C.www.ct-Single-Minute Exchange of Die(SMED)Left column:non-value-adding setup

46、and load/unload activities Right column:value-adding machining activities50 2009,Levinson Productivity Systems,P.C.www.ct-SMED Principles and Benefits1.Internal setup requires the tool to stop.Reduce internal setup time,or convert internal to external setup.2.External setup can be performed while th

47、e tool is working on another job.3.SMED reduces cycle time by facilitating smaller lot sizes,mixed model production,and/or single-unit flow51 2009,Levinson Productivity Systems,P.C.www.ct-Error-Proofing(Poka-Yoke)Error-proofing makes it difficult or impossible to do the job the wrong way.Slots and k

48、eys,for example,prevent parts from being assembled the wrong way.Process recipes and data entry also can be error-proofed.52 2009,Levinson Productivity Systems,P.C.www.ct-Summary and ConclusionMost of lean manufacturing is common sense!53 2009,Levinson Productivity Systems,P.C.www.ct-SummaryBusiness

49、 activities can contain enormous quantities of built-in waste(muda,friction).The greatest obstacle to the wastes removal is usually failure to recognize it.Lean manufacturing includes techniques for recognition and removal of the waste.This delivers an overwhelming competitive advantage.54 2009,Levinson Productivity Systems,P.C.www.ct-