SPC高级教程4

SPC-advancedtrainingcourseX-R控制图SPC-advancedtrainingcourse過程控制a)計算及繪畫控制限-樣本容量低於7時，極差並沒有LCLSPC-advancedtrainingcourse解释控制图UCLLCLAvgUCLLCLAvgChangeinlevelChangeinvariabilitySPC-advancedtrainingcourse解釋控制圖-確定是否有不受控的情況-檢查過程記錄，找出並列明任何特殊原因。-再計算控制限。控制上限(UCL)中線控制下限(LCL)控制上限(UCL)中線控制下限(LCL)受控過程不受擯過程SPC-advancedtrainingcourseUCLLCLAABCCBUCLLCLAABCCBUCLLCLAABCCBUCLLCLAABCCBTest1.OnePointBeyondZoneATest2.NinePointsinaRowonOneSideoftheCenterLineTest3.SixPointsinaRowSteadilyIncreasingorDecreasingTest4.FourteenPointsinaRowAlternatingUpandDownxxxxxx控制图失控检验SPC-advancedtrainingcourseUCLLCLAABCCBUCLLCLAABCCBUCLLCLAABCCBUCLLCLAABCCBTest5.TwoOutofThreePointsinaRowinZoneAorBeyondTest6.FourOutofFivePointsinaRowinZoneBandBeyondTest7.FifteenPointsinaRowinZoneC(AboveandBelowCenterline)Test8.EightPointsinaRowonBothSidesofCenterlinewithNoneinZoneCxxxxxxx控制图的失控检验SPC-advancedtrainingcourseUCLLCLAABCCB控制图失控检验OnepointaboveUCLTwooutofthreesuccessivepointhereoraboveFouroutoffivesuccessivepointhereoraboveSevenoutofeightsuccessivepointhereoraboveOnepointaboveLCLTwooutofthreesuccessivepointhereorbellowFouroutoffivesuccessivepointhereorbellowSevenoutofeightsuccessivepointhereorbellow3s2s1s-3s-2s-1s034.1%13.6%34.1%13.6%2.2%2.2%0.1%0.1%SPC-advancedtrainingcourse20100ObservationNumberUCLLCL20100ObservationNumberUCLLCLSeasonalTrends:Thesecouldbecausedbysystematicchangeslike:temperature,operatorfatigue,voltageorpressurefluctuations,etc.Mixtures:Aclearindicationiswhenmostofthepointsareclosetothecontrollimits,andalmostnopointsnearthecenterline.Theseareusuallyduetounderestimatingtheprocessvariabilityor“over-control”,whereoperatorsintervenewiththeprocessfrequentlytryingtorespondtoinherentvariabilityinsteadofassignablecauses.Thisalsooccurswhencontrollingtwoprocessesonthesamechart.控制图的趋势判断规则SPC-advancedtrainingcourse20100ObservationNumberUCLLCL151050ObservationNumberUCLLCLChangesinprocessmeans:Theseareusuallyduetotheintroductionofnewoperators,machines,procedures,etc.Canalsohappenbecauseofprocessimprovements.Upward/DownwardTrends:Continuoustrendingonthesamedirection.Theseareusuallycausedbycomponentwearamongothers.控制图的趋势判断规则SPC-advancedtrainingcourse20100ObservationNumberUCLLCL“WhiteSpace”:Pointstendtoclusteraroundthemean.Usuallycausedby:(1)incorrectcontrollimits(overestimatingprocessvariability),(2)continuousimprovementspaying-off.Limitsshouldberecalculatedwhenthissituationisfound.控制图的趋势判断规则SPC-advancedtrainingcourse製程控制對特殊原因採取的措施1.即時分析失控情況是非常重要的，以便將不符合規格的產品減至最少；並取得新的數據作調查分析。2.特殊原因可以是正面或負面3.在控制圖中，我們可能會在任何單值子組中得到一個特殊原因的錯誤信息。SPC-advancedtrainingcourseExampleofOCAPinW7PT