1、Introduction of Six SigmaBelton GroupRex WongScope of ModulenWhat is Six SigmanWhy the need for Six SigmanHow to apply Six SigmaWhat is Six Sigma? is a comprehensive and flexible system for achieving, sustaining and maximizing business success. It is uniquely driven by close understanding of custome
2、r needs, disciplined use of facts, data and statistical analysis, with diligent attention to managing, improving and reinventing business processes.Peter S Pande, Robert P Neuman, Roland R Cavanagh (McGraw Hill, 2000) Is Three ThingsA statistical measurementA business strategyA philosophy A Statisti
3、cal MeasurementnIt provides a quantitative performance assessment of our products, services and processes.nIt allows for comparisons against other similar or dissimilar products, services and processes.nIt provides feedback on how far ahead or behind we are.Six Sigma helps to establish our course an
4、d to gauge our pace in the race for total customer satisfaction.Six Sigma A business strategyImproved Sigma-Rating of ProcessImproved Product or Process QualityReduced Cost of OperationsGreater Customer SatisfactionCost Of Poor Quality (COPQ)Traditional Quality Costs(tangible)Lost OpportunityHidden
5、FactoryAdditional Costs of Poor Quality(intangible)(Difficult or impossible to measure)COPQ is a function of Sigma Capability InspectionWarrantyScrapReworkRejectsMore SetupsExpediting CostsLost salesLate DeliveryLost Customer LoyaltyExcess InventoryLong Cycle-TimesEngineering Change OrdersCost Of Po
6、or Quality (COPQ)ProfitTotal Cost to Manufactureand DeliverProductsProfitTheoreticalCostsCost ofPoor QualityCOPQPrice ErosionTheoreticalCostsCost ofPoor QualityCOPQProfitTheoreticalCostsCOPQ3) Six Sigma A philosophynSix Sigma is about working smarter, not harder.nDiscover and neutralize harmful sour
7、ces of variationnMistakes are reduced (or eliminated)nImproved process capabilitynSigma rating goes upQuality BreakthroughTimeReject RateHistorical Level ( 0)Natural Variation under 0 (30)Special VariationOptimum Level ( 1)Natural Variation under 1(31)Why needs of Six Sigma?nThe goal of is not to ac
8、hieve six sigma levels of quality (i.e. 3.4 dpmo).Six Sigma is about improving profitability; improved quality and efficiency are immediate by-products.Six Sigma aggressive goalSigma is a statistical unit of measure that reflects process capability. The sigma scale of measure is perfectly correlated
9、 to such characteristics as defects-per-unit, parts-per million defective, and the probability of a failure/error.2308,537366,80746,210523363.4 PPMProcessCapabilityDefects per Million Opp.Six Sigma Process Point of Inflection1 TUSLp(d)1234563 This is a 6 Sigma ProcessBenefit of Six SigmanCost reduct
10、ionnProductivity improvementnMarket-share growthnCustomer retentionnCycle-time reductionnDefect reductionnCulture changenProduct/service developmentCustomers Needs Internal MetricsDeliveryPriceQualityCustomerSupplierNeedCycle TimeCostDefectsDoHow to apply Six Sigma?nUnlike conventional improvement p
11、rograms which focuses on improving the defects on the “output”, Six Sigma focuses on the “process” that creates or eliminates the defects.nSix Sigma seeks to reduce variability in a process by means of a systematic approach called the Breakthrough Strategy.Six Sigma approachIdentify the Customers Ne
12、edCenter around the TargetReduce VariationReduce DefectsFocus of Six Sigma?The output (Y) is perceived as a function of the input (X).Breakthrough Strategy DefinenThe phase sets the stage for a successful project by addressing the following questions: What is the problem of our focus? Whats our goal
13、? And by when? Whos the customer impacted? What are the CTXs in-concern? Whats the process under investigation?Project DefinitionnImprove time to market for all productsnLead the industry in key technologiesnCreate world-class manufacturing processesnDevelop strategic supplier relationshipsnProvide
14、best-in-class product and process qualitynDevelop strategic relationships with key customersnBecome an employer of choiceBaseline Metric DataThe average long-term defect level of a process when all input variables in the process are running in an unconstrained fashion.The best-case short-term defect
15、 level of a process when all input variables in the process are centered and in-control.The defect level of the process deemed by comparison to be the best process possible.Breakthrough ImprovementTimeReject RateBaseline NID( 0, 0)Natural Variation (30)Special VariationGoal NID( 1, 1)Natural Variati
16、on (31)EntitlementOpportunity for Improvement ()0.7Cost of QualityInternal Failure CostsExternal Failure Costs Scrap Cost to Customer Rework Warranty Cost Supplier Scrap & Rework Returned MaterialAppraisal CostsPrevention Costs Inspection Quality Planning Testing Process Planning Quality Audits Proc
17、ess Control Initial & Maintenance Costs of Training Test & Inspection EquipmentOpportunity CostsHard Savings Potential Savings Soft SavingsMeasurelThe phase serves to validate or refine the problem, and to begin the search for root causes. It addresses the focus and extent of the problem, based on m
18、easures of the process, the key data required to narrow the problem to its major factors or vital few root causes.Capability Analysis Conventional Metricsnin (e.g. 7.4%)nin (e.g. 0.074)nin (e.g. 74,000 DPPM)Capability AnalysisCapability AnalysisReject rateYieldConventional MetricsIn precentIn RatioI
19、n parts per million In first-time yieldIn final yield(eg, 7.4%)(eg,.074)(eg, 74,000 dppm)Six Sigma MetricsIn defects per Unit (DPU)In defects per million opportunities (DPMO)In throughput yieldIn rolled throughput yieldIn normalized yieldDefect per unit (DPU) : The average number of defects per unit
20、 produced.Defect Rate = # Defects / # Units = 7 / 5 = 1.4 dpuDefects Per Million Opportunities (DPMO) : The number of possibilities for defect creation in any unit of product process or sequence of processes.1. Arm Height2. Arm thickness3. Bore hole Dia4. Swgae hole Dia5. Roughness6. Teardrop profil
21、e7. Roll8. PitchOpportunities per Unit = 8Number of Opportunities= Opportunities per Unit Number of Units= 8 5 = 40Defect Rate= # Defects / # Opportunities = (7 / 40 ) 106= 175,000 dpmoDPMO vs Sigma Capability 0.023.42336,21066,811308,770697,672-100,000200,000300,000400,000500,000600,000700,000800,0
22、0001234567Sigma CapabilityDefects Per Million OpportunityFirst-time yield (Yft) is the number of units that pass a particular inspection, compared with the total number of units that pass through that point in the process.Process968Accept32RejectFirst-Time Yield, Yft = 968 / 1000 = 0.9681,000InputTh
23、roughput yield (Ytp) is the probability that a unit of product or service will pass through a given process step error-free.nThroughput Yield, Ytp = eDPUProcess968Accept32Reject1,000Input(40 Defects)Throughput Yield, Ytp = e-(40/1000) = 0.961Final Yield (Yf)800ShipProcess A1,000Input50ScrapProcess B
24、950Input25ScrapProcess C925Input125ScrapFinal Yield, Yf= Quantity Shipped / Quantity Built = 800 / 1,000 = 0.80A shortcoming of final yield is that it fails to consider the “hidden factory” or rework.Hidden Factory : ad hoc systems and processes set up to correct errors made during the mainstream pr
25、ocess.Rolled Throughput Yield (Yrp)Rolled Throughput Yield= Ytp(A) Ytp(B) Ytp(C) = 0.7408 0.6393 0.5824= 0.2758675ShipProcess A1,000Input50ScrapRework200150Process B800Input (950)25ScrapRework300275Process C650Input(925)125ScrapRework250125Defects = 300 Ytp(A)= e300/1,000 = 0.7408Defects = 425 Ytp(B
26、)= e425/950 = 0.6393Defects = 500 Ytp(C)= e500/925 = 0.5824Defects= 300Rolled Throughput Yield (Yrp)The rolled throughput yield is the probability that a unit of product or service is able to pass through the entire process defect-free.It is a function of the defect rate, and hence provides a better
27、 estimate of the amount of rework required.Rolled throughput yield can be improved by having higher throughput yields at each process step reducing the number of process stepsSigma ValuenThe sigma value is derived from the probability of a defect in a process and is used to compare performance acros
28、s products or processes nz-Score is most accurately determined by using the equation of z = eAnalyzenIn the phase, practical business problems are turned into statistical problems. The statistical tools and the order in which they are applied will depend on the problem and process, and the approach
29、to the problem.Analyze Data/ProcessDevelop Causal HypothesisRefine or Reject HypothesisAnalyze Data/ProcessConfirm & Select Vital Few CausesImprovenThe phase seeks to address the following: What possible actions or ideas required to address the root cause of the problem, and to achieve the goal? Whi
30、ch of the ideas are workable potential solutions? Which solution will most likely achieve the goal with the least cost or disruption? How can the chosen solution be tested for effectiveness, and then implemented permanentlyControlnIn the phase, actions are established to ensure that the process is m
31、onitored continuously for consistency in quality of the product or service.Implement ongoing measures and actions to sustain improvementDefine responsibility for process ownership and managementExecute “closed-loop” management and drive towards Six SigmaRealizationlIn the phase, ownership of the pro
32、ject is transferred to the finance representative, for tracking of financial benefits of the project.ChampionBlack BeltnAct as experts and enthusiasts.nIdentify the barriers.nManagement of project: from planning, through execution, to realization.nReport progress to appropriate leadership levels.nDe
33、termine the most effective tools to apply.nGather input from knowledgeable sources, from operators to managers.nGreen Belt TrainingnMonitor & provide guidance of Green Belt projects.Green BeltnFunction as Green Belts on a part-time basis, while performing their regular operational duties.nParticipat
34、e in Black Belt teams in the context of their existing responsibilities.nLearn the methodology as it applies to a particular project.nContinue to learn and practice the methods and tools after project completion.Process FlowChampionManagementEmployeesFinanceTeamBlack BeltSix Sigma RoadmapOptimized P
35、rocess30 - 5010 - 154-8Key Process InputVariables (KPIVs)8 - 10KPIVsCritical KPIVs3-6Key Leverage KPIVsInputs VariablesProcess MapMulti-Vari Studies,CorrelationsScreening DOEsDOEs, RSMC&E Matrix and FMEAGage R&R, CapabilityT-Test, ANOM, ANOVAQuality SystemsSPC, Control PlansMeasureAnalyzeImproveControlWhat you have learnt?nWhat is Six Sigma?nA statistical measurementnA business strategynA philosophyEnd of PresentationRev 1 23 Apr 02
