《《精编》Statistical Process Control（英文版）》由会员分享，可在线阅读，更多相关《《精编》Statistical Process Control（英文版）（40页珍藏版）》请在金锄头文库上搜索。
1、ToolsforManagersStatisticalProcessControlProfessorStephenR LawrenceCollegeofBusinessandAdministrationGraduateSchoolofBusinessAdministrationUniversityofColoradoDenver Colorado CausesofVariation NaturalCauses AssignableCauses Whatpreventsperfection Processvariation InherenttoprocessRandomCannotbecontr
2、olledCannotbepreventedExamplesweatheraccuracyofmeasurementscapabilityofmachine CausesofVariation NaturalCauses AssignableCauses Whatpreventsperfection Processvariation ExogenoustoprocessNotrandomControllablePreventableExamplestoolwear Monday effectpoormaintenance InherenttoprocessRandomCannotbecontr
3、olledCannotbepreventedExamplesweatheraccuracyofmeasurementscapabilityofmachine ProductSpecificationandProcessVariation Productspecificationdesiredrangeofproductattributepartofproductdesignlength weight thickness color nominalspecificationupperandlowerspecificationlimitsProcessvariabilityinherentvari
4、ationinprocesseslimitswhatcanactuallybeachieveddefinesandlimitsprocesscapabilityProcessmaynotbecapableofmeetingspecification ProcessCapability LSL USL Spec CapableprocessVerycapableprocessProcessnotcapable Processvariation ProcessCapabilityIndexI Measureofcapabilityofprocesstomeet fallwithin specifi
5、cationlimits ProcessCapabilityIndexI Measureofcapabilityofprocesstomeet fallwithin specificationlimitsTake width ofprocessvariationas6 LSL USL Spec 6 3 ProcessCapabilityIndexI Measureofcapabilityofprocesstomeet fallwithin specificationlimitsTake width ofprocessvariationas6 LSL USL Spec 6 3 99 7 Proc
6、essCapabilityIndexI Measureofcapabilityofprocesstomeet fallwithin specificationlimitsTake width ofprocessvariationas6 If6 USL LSL thenatleast99 7 ofoutputofprocesswillfallwithinspecificationlimits LSL USL Spec 6 3 99 7 ProcessCapabilityIndexII DefineProcessCapabilityIndexCpas IfCp 1 0 processis capa
7、bleIfCp 1 0 processis notcapable ProcessCapability Example Amanufacturerofgranolabarshasaweightspecification2ouncesplusorminus0 05ounces Ifthestandarddeviationofthebar makingmachineis0 02ounces istheprocesscapable ProcessCapability Example Amanufacturerofgranolabarshasaweightspecification2ouncesplus
8、orminus0 05ounces Ifthestandarddeviationofthebar makingmachineis0 02ounces istheprocesscapable USL 2 0 05 2 05ounces ProcessCapability Example Amanufacturerofgranolabarshasaweightspecification2ouncesplusorminus0 05ounces Ifthestandarddeviationofthebar makingmachineis0 02ounces istheprocesscapable US
9、L 2 0 05 2 05ouncesLSL 2 0 05 1 95ounces ProcessCapability Example Amanufacturerofgranolabarshasaweightspecification2ouncesplusorminus0 05ounces Ifthestandarddeviationofthebar makingmachineis0 02ounces istheprocesscapable USL 2 0 05 2 05ouncesLSL 2 0 05 1 95ouncesCp USL LSL 6 2 05 1 95 6 0 02 0 1 0
10、12 0 85 ProcessCapability Example Amanufacturerofgranolabarshasaweightspecification2ouncesplusorminus0 05ounces Ifthestandarddeviationofthebar makingmachineis0 02ounces istheprocesscapable USL 2 0 05 2 05ouncesLSL 2 0 05 1 95ouncesCp USL LSL 6 2 05 1 95 6 0 02 0 1 0 12 0 85 Therefore theprocessisnot
11、capable ProcessCentering LSL USL Spec CapableandcenteredCapablebutnotcenteredCapablebutnotcentered ProcessCentering Example Forthegranolabarmanufacturer iftheprocessisincorrectlycenteredat2 05insteadof2 00ounces whatfractionofbarswillbeoutofspecification ProcessCentering Example Forthegranolabarmanu
12、facturer iftheprocessisincorrectlycenteredat2 05insteadof2 00ounces whatfractionofbarswillbeoutofspecification 2 0 LSL 1 95 USL 2 05 ProcessCentering Example Forthegranolabarmanufacturer iftheprocessisincorrectlycenteredat2 05insteadof2 00ounces whatfractionofbarswillbeoutofspecification 2 0 LSL 1 9
13、5 USL 2 05 ProcessCentering Example Forthegranolabarmanufacturer iftheprocessisincorrectlycenteredat2 05insteadof2 00ounces whatfractionofbarswillbeoutofspecification Outofspec ProcessCentering Example Forthegranolabarmanufacturer iftheprocessisincorrectlycenteredat2 05insteadof2 00ounces whatfracti
14、onofbarswillbeoutofspecification 50 ofproductionwillbeoutofspecification Outofspec Example ProcessCapability ProcessControlCharts EstablishcapabilityofprocessundernormalconditionsUsenormalprocessasbenchmarktostatisticallyidentifyabnormalprocessbehaviorCorrectprocesswhensignsofabnormalperformancefirs
15、tbegintoappearControltheprocessratherthaninspecttheproduct Statisticaltechniquefortrackingaprocessanddeterminingifitisgoing outtocontrol ProcessControlChartsTheoryI UpperSpecLimit LowerSpecLimit TargetSpec ProcessControlChartsTheoryI UpperSpecLimit LowerSpecLimit 6 3 TargetSpec ProcessControlChartsT
16、heoryI UpperSpecLimit LowerSpecLimit UpperControlLimit LowerControlLimit 6 3 TargetSpec ProcessControlChartsTheoryII UpperControlLimit UCL LowerControlLimit LCL 6 3 NaturalVariation ProcessControlChartsPractice UCL Target LCL Time Samples ProcessControlCharts Practice UCL Target LCL Samples Time Naturalvariation ProcessControlCharts Practice UCL Target LCL Samples Time Incontrol Naturalvariation ProcessControlCharts Practice UCL Target LCL Samples Time Incontrol Naturalvariation ProcessControlCh
