introduction to six sigma

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  • 1. Six Sigma Overview

2. 4 Sigma Process Capability 99.38% Current Standard6 Sigma Process Capability 99.99966% World-ClassLong-Term Yield3 Sigma Process Capability 93.32% Historical StandardThe Classical View of Performance Six-Sigma is a philosophy: Why isnt 99% acceptable good enough...?? 20,000 lost articles of mail every hour. 15 minutes each day of unsafe drinking water. 5,000 incorrect surgical procedures per week. 4 or more accidents per day at major airports. 200,000 wrong drug prescriptions each year. 7 hours each month without electricity. 3. History of 6 Sigma 6 Sigma manufacturing philosophy came from MotorolaThey recognised that sufficient process improvement would notoccur using a conventional approach to quality. It was developedto help them reduce variation within a process by focusing efforton improving inputs to a process rather than reacting to outputs. The process was failing the customer expectations Traditionally, processes aimed for process capability of 3 to 4sigma (Cpk=1.0 to 1.33 or 93% to 99.3% acceptable) The customer received 6200 defective product per million at best Processes now aim for 6 sigma (Cpk=2) The customer would receive 3.4 defective product per millionOn target, minimum process variation 4. 6 sigma Process CapabilityWhat is it (CPK) 3 Sigma ( Process capability of 1 CPK ) if the process (lorry) slightly varies then the scrap or damage willoccur 6 Sigma ( Process capability of 2 CPK ) if the process (lorry) varies, there will be no scrap or damageCurbs= requiredprocess tolerancesCPK of 2(6 sigma)CPK of 1(3 sigma) 5. Variation exists in everything. Even thebest machine cannot make every unitexactly the same. Improved capability, becomes a necessity,due to the need of : improved designs lower costs better performance All of this leads to the need of tightertolerances This means that the ability to operate to atight tolerance, without producing defectsbecomes a major advantageUnderstanding Variability 6. Improvement methodologyOn target,minimum process variationKPIVKeyProcessInputVariablesThe ProcessX1 X2 X3Controllable InputsN1 N2 N3Inputs:Raw materials,components, etc.Uncontrollable InputsY1, Y2, etc.QualityCharacteristics:Outputs 7. D M A I CD M A I CDefineMeasureAnalyzeImproveControlImprovement methodology 8. DefineImprovement methodology Define terms of reference (Charter theproject) Team / customer / project charter Brain storming Mind maps Affinity diagrams High level Process Maps Systematic diagrams / Fault tree Business Process Mapping Define customer requirements (Voice ofthe customer) QFD Quality Function DeploymentTo develop a team charter.To define the customersand their requirements(CTQ Critical to Quality).To map the businessprocess to be improvedCharacteristicsImportance out of 10Product / customers 9. Define Define terms of reference (charting a project) What you can deliver to the customer and the support you needfrom the customer to facilitate a successful improvement (contractof engagement) Brain storming, Mind maps, Affinity diagrams, High level ProcessMaps, Systematic diagrams / Fault tree, Business Process Mapping Tools to explore a problem, project or current thinking. Tools to group those ideas logically. Then define a route map to improvement, the risk involved andhow to mitigate that risk. Define customer requirements (Voice of the customer) QFD Quality Function Deployment, is a method of defining whatthe customer needs, what is critical to there business success &prioritise objectives to meet the customer need. 10. MeasureImprovement methodology Voice of the process Data Collection - 7 quality tools Tally charts Bar charts Pareto Run charts Control charts Cause & effect Check sheets Evaluate measurement systems Gauge R&R Select measures of performance Quality Function DeploymentTo measure andunderstand baselineperformance for thecurrent process 11. Measure Voice of the process (7 quality tools) Tally charts, Bar charts, Pareto, Run charts, Control charts, Cause& effect, Check sheets. Evaluate measurement systems Gauge R&R Every process has variation and measurement system, tools &cmm are no exception. Typical your measurement process needs to be ACCURATE,REPEATABLE & REPRODUCIBLE to less than 10% of thetolerance you are trying to measure to & proven to be so. Select measures of performance QFD Quality Function Deployment is a method of defining whatthe customer needs and what is critical to there business successand prioritising performance measures to support the customersneed. 12. AnalyzeImprovement methodology Investigate source of variation(Special cause / Common causes) Stratification of data to get information Cause & effect CP & CPK Fault tree Contingence analysis FMEA (Failure Mode Effect Analysis) Design of experiments (DOE) Detailed process mapsSeek to:-PrioritiseUnderstandCluesCausesMonitor improvementsLook for signals 13. LostShoeLostNailLostHorseLostSoldierLostBattleWhy Battles are LostWhy Battles are LostCurrent Window of ConsiderationCause FailureModeEffectFMEAIdentifies the ways in which a product or process can failEstimates the risk of specific causes with regard to these failuresPrioritizes the actions that should be taken to reduce the chance of failureFMEA(failure mode effect analysis) 14. factors which shift the averagefactors which affect variationfactors which shift the average and affectvariationfactors which have no effectA1 A2D1=D2B1B2C1C2DOE - (design of experiments)will help us identify... 15. DOE - (design of experiments)Measure the ProcessThe ProcessX1 X2 X3Controllable InputsN1 N2 N3Inputs:RawMaterials,components,etc.Uncontrollable InputsY1, Y2, etc.QualityCharacteristics:OutputsLSL USLEstablish theperformancebaselineProcessStep/InputPotential Failure Mode Potential Failure EffectsSEVPotential CausesOCCCurrent ControlsDETRPNActionsRecommendedLoad DMF/DMFLoad Accuracy MischargeofDMF Viscosity out of spec 7 SOP not Followed 5Operator Certification/ ProcessAudit5 175Fool proofthis processusinginput from TQLTeamSteam toDICY/ScaleAccuracyScaleNot Zeroed MischargeDMF 3 Faulty Scale 2 None 9 54Include Daily sign-off ofScale funtionin Shiftset-up verification.Load DMF/DMFLoad Accuracy MischargeofDMF Viscosity out of spec 7 EquipmentFailure 2Maintenance Procedure (SOP5821)/VisualCheck3 42Steam toDICY/ScaleAccuracyScale> 0 Low DMF Charge 3 Waterin Jacket 2 Visual Check ofJacket(SOP 5681) 4 24Steam toDICY/ScaleAccuracyScale Inaccurate High DMFCharge 3 Tank Hanging Up 2 Visual Check (SOP 5681) 4 24 16. DOE - (design of experiments) Analyse theProcessThe ProcessX1 X2 X3Controllable InputsN1 N2 N3Inputs:RawMaterials,components,etc.Uncontrollable InputsY1, Y2, etc.QualityCharacteristics:OutputsLSL USLKey Outputs: Variable How Measured When Measured123Noise Variables: Variable How Measured When Measured12345Controllable Inputs Variable How Measured When Measured12345Overall Sampling Plan:Run Temperature Pressure1 Hi Hi2 Hi Hi3 Lo Hi4 Lo Hi5 Hi Lo6 Hi Lo7 Lo Lo8 Lo Lo3 .52 .51.5Capability Histogram43213 .02 .52 .01.5Xbar and R ChartS u b g rMeansM U =2 .3 7 6U C L =2 .5 6 8L C L =2 .18 30 .90 .60 .30 .0RangesR =0 .5 16 2U C L =0 .9 6 2 1L C L =0 .0 7 0 2 74321Last 4 Subgroups3 .02 .52 .01.5Subgroup N um berValues412 .9 19 5 81.8 3 17 5Cp: 2.76CP U: 2.99CP L: 2.53Cpk : 2.53Capability PlotProc ess Toleranc eSpec ific ationsSt D ev : 0.181306IIIIII3 .52 .51.5Norm al Prob P lotC ap ab ility us ing P o o le d S tand ard D e viatio n 17. DOE - (design of experiments) Improve theProcessUncontrollable InputsThe ProcessX1 X2 X3Controllable InputsN1 N2 N3Inputs:RawMaterials,components,etc.Y1, Y2, etc.QualityCharacteristics:OutputsXXXLSL USLLSL USLScrewRPMPrimWdthNip FPMThree Factor Design 18. DOE - (design of experiments) Control theProcessThe ProcessX1 X2 X3Controllable InputsInputs:RawMaterials,components,etc.N1 N2 N3Uncontrollable InputsY1, Y2, etc.QualityCharacteristics:Outputs LSL USLCheckListsErrorProofingWorkInstructions5 Cs 19. Analyze Investigate source of variation (Special cause / Common causes) Special cause variation are the one off, occasional and obviouscause of a process / quality problems. Common cause variation are the day in day out causes of processproblems, because the process is not stable enough, they arehidden (these form 80% of process problems) Conventional non-conformance management systems seek to solvespecial cause variation (e.g. concessions) - but these only represent15 - 20% of the total variation. 6 Sigma addresses all variation. 20. ImproveImprovement methodology Prioritise improvements Impact Vs Effort Brainstorming Affinity diagrams Solution selection matrix Tactical implementation plans Deliver improvements (reduce variationsystematically)Customer protectionGet controlImprove process 21. Improve Prioritise improvements Tool commonly in uses are, Impact Vs Effort,Brainstorming, Affinity diagrams, Solution selectionmatrix. These tools help define the best method to meet thecustomer need (as defined in the QFD) Tactical implementation plans Deliver improvements to reduce variationsystematically i.e. make a change, note theimprovement and make the next improvement. Critical we need to establish that any change is achange for the good. 22. ControlImprovement methodology Control the process Recover Control plans Escalation process Prevent Poke yoke (mistake/ error proof) Monitor Control charts Checksheets Documentation and Standardisation 23. Control Control the process Recover, Control plans, Escalation process. Prevent by Poke yoke (fool proof the process) to fundamentallyremove the rood causes of process variation. Monitor, Control charts, Checksheets, Documentation andStandardisation, to ensure that stable process is maintained andthat the process does not degrade. The objective is to remove the root causes of process variation,management are only left with a few critical i