1_11al process capability strategies.ppt

processcapabilityanalysis,overviewbrief,collecttimelydata,processstable/consistent?(spc),processacceptable?(capability,z),developmeasureswithrespecttostandards,identifystandards(specs)thataddresscustomerrequirements(ctqs),yes,no*,yes,analyzephase,use“specialcausestrategy”(howtoimproveanunstablesystem)actquicklytosearchforthecause:whatwasdifferent?whichxjustexerteditsinfluence?,“messageisinasinglepoint”,use“commoncausestrategy”(howtoimproveastablesystem)investigaterelationshipsamonginputs(xs)andoutput(y)via:multi-varistudy(stratification)experimentation(doe)disaggregation(breakintocomponents),“messageisinallthepoints”,measurephase,focus,define,processmap,c&e,fmea,etc.,evaluatemeasurementsystem(msa),improvephase,plan&implementshort-termremedy(immediatecontainment)plan&implementlong-termremedyverifyimpact/success(beforevsafter),plan&implementlong-termremedyverifyimpact/success(beforevsafter),controlphase,modifycontrolplans:holdgainscompletehand-offactivitiesensurenewproceduresareusedandareeffectivemonitorforinnovation&improvementopportunitiesmonitorever-changingcustomerneedsandrequirements,no,*=thisdatafromanunstable,unpredictableprocesscanstillbeusedfora“pseudo-capabilitystudy”-arough“beforevsafter”guessathowmuchprogressmaybepossibleifwesucceedinimprovingthe“approximatez(lt)”(using“overallstddev”)toz(st).,developedbyw.scottlasater-geics,define,whatsortsofdatadoyouseebeingcollectedaroundyourarea?,(listthembelow),_,attributesdata,variablesdata,howtogetcapabilityindicesviaminitab,(1)variablesdata(2)attributesdata,.aquicklook,openfile“capab_v.mtw”.characterizeprocesscapability.lsl=40andusl=100whattypeofdataisthis(attributeorvariables)?variableszshortterm=4.67zlongterm=3.74,yourcapabilitystudyon“percentlateshipments”overthepastfourweekshasrevealedattotalof400“late”outofatotalof4000shipments.characterizeprocesscapability.whattypeofdataisthis(attributeorvariables)?attributezshortterm=2.782zlongterm=1.282,importantnote:x-barchartshowsunstableprocess-mayevenbe2differentprocesses.,minitabcommand:sixsigma/processreport/singlecolumnoutput/subgroupsizesubgroup,(seenextpagesfordetails),capabilityforvariablesdata,openfile“capab_v.mtw”.characterizeprocesscapability.lsl=40andusl=100whattypeofdata?variablesdatazshortterm=4.67zlongterm=3.74,importantnote:x-barchartshowsunstableprocess-mayevenbe2differentprocesses.,.thenclickok.,report#1,note:x-barchartshowsunstableprocess,maybe2differentprocesses,report#2,yourcapabilitystudyon“percentlateshipments”overthepastfourweekshasrevealedattotalof400“late”outofatotalof4000shipments.characterizeprocesscapability.whattypeofdata?attributedatazshortterm=2.782zlongterm=1.282,example1defect=1lateshipment4001unit=1shipment40001opportunityfordefectperunit1,capabilityforattributesdata,.thenclickok.,note:zbench=zsttriangleshowsthatzstissomewhereslightlylessthan3.,example:ifaprocesshas10%rejectrate,wewouldsayithasacapabilityofz(lt)=1.28andz(st)=2.78,z-tableforattributedata:%rejectedtoz(lt),thenz(lt)+1.5=z(st),processcapability:theconceptsbehindthecalculations,y=weight(lbs),220,160,100,process=hose,1drop=1unitofoutput,histogramis.apileofindividualvalues,dotplot,:.:.:.:.:.:.:.:.:.:.:.:.-+-+-+-+-+-+-c1100125150175200225,dotplots,1stobservation,2ndobservation,1.1,1.0,1.15,1.2,1.25,1.3,1.35,1.4,1.05,supposewehaveamanufacturinglinethatisproducingshafts.diametersrangefrom1.0to1.4inches.aswemakeameasurementofashaft,werecordthevaluewithadotontheabovescaleex:1stobservation=1.4inches2ndobservation=1.1inches,andsupposewecontinuesamplinguntil150shaftshavebeenmeasuredwhatstatementscanyoumakeaboutourprocess?,:.:.:.:.:.:.:.:.:.:.:.,dotplots,1.1,1.0,1.15,1.2,1.25,1.3,1.35,1.4,1.05,:.:.:.:.:.:.:.:.:.:.:.,dotplots,1.1,1.0,1.15,1.2,1.25,1.3,1.35,1.4,1.05,nowimaginethesamedata,groupedintointervalswithbarsusedtorepresenthowthedata“looks”.,datarepresentedjustwiththedotsiscalledadotplotusingdatarepresentedintheabove“barformat”iscalledahistogram,histogramdistribution,histogram,nowwevecombinedthehistogramwithourlowerandupperspecifications.question#1:whatarespecifications?wheredotheycomefrom?question#2:whatcanyousayaboutourprocessnow?,histogram,supposethecustomerhasgivenusnewspecifications!question:whatcanyousayaboutourprocessnow?,1.1,1.3,uclandlclversususlandlsl,uppercontrollimits=ucllowercontrollimits=lcl,upperspecificationlimits=usllowerspecificationlimits=lsl,ifapointfallsbeyondtheuclorlcldoesthismeanwearemakingadefectiveitemforthecustomer?,time,y-axis(response),uclandlclversususlandlsl,uppercontrollimits=ucllowercontrollimits=lcl,upperspecificationlimits=usllowerspecificationlimits=lsl,istheprocessbelowmakingdefectiveitems?,ucl,lcl,time,y-axis(response),usl,lsl,uclandlclversususlandlsl,uppercontrollimits=ucllowercontrollimits=lcl,upperspecificationlimits=usllowerspecificationlimits=lsl,istheprocessbelowmakingdefectiveitems?,ucl,lcl,time,y-axis(response),usl,lsl,thegoal.,phaseone-unpredictableperformance,-variation(special/naturalcauses),-unpredictable(hourly,daily),-detectandeliminatespecialcauses,phasetwo-stability,-incontrol,-naturalvariationonly,howweprogresstowardthegoal,not“capable”ofgettingallthewateroutputintotheclownsmouth?,whichapproachtouse?specialcausestrategy?commoncausestrategy?,incontrol,butnotcapable,(variationfromcommoncausesexcessive),incontrolandcapable,(variationfromcommoncausesreduced),howweprogresstowardthegoal,nowitis“capable”ofgettingallthewateroutputintotheclownsmouth-withextraelbowroomforunexpectedshifts&drifts(i.e.,someonebumpsyourarm).,whichapproachtouse?specialcausestrategy?commoncausestrategy?,variablesdata,0%rejected,target,attributesdata,thegoalis.,(1)pretendingthatistayperfectlycentered,isitevenpossibleforthisvantofitinthere?(.aspreadwidthissue)(2)now,takingintoconsiderationmypaststeering(centering)performance,amiabletomakeitwithoutbumpingthewalls/boundaries(thecustomerspecifications)?(.bothspreadandcenteringissues),itssortofliketryingtodriveau-haulmovingvan/truckthroughatunnel.,z(shortterm),z(longterm),“shortterm”capabilityvs“longterm”performance,later,welldiscusstheimportanceandimplicationsofconsistency(stabilityovertime)andthelackthereof.spread:howwouldmyestimating/predictingabilitybeaffectedifmytrucksbodyhadbeenunexpectedlyexpandingandcontractingonoccasion?centering:howwouldmyestimating/predictingabilitybeaffectedifmysteeringhadbeenshiftingsignificantlyandunexpectedlyeveryonceinawhile?,notes:,capabilityanalysisroadmapvariablesdata(i.e.,continuousdata)part1,start,evidenceofinadequatemeasurementunits?,spreadstable?rormrchartshowreasonabledegreeofstatisticalcontrol?,calculatez(st)orcp,centeringstable?xorx-barchartshowreasonabledegreeofstatisticalcontrol?,histogram,nmlplot,andnmltestindicatenormality?,calculatez(lt)orcpk,dataistoodiscrete.controlchartsandcapabilityindicesunreliable.needtoimprovemeas.process.,yes,t