统计过程控制-测量系统分析

1、 SPCnStatistic Process ControlStatistic techniqueProcess ControlSPC由由Product Spec到到Process Parameter由由Product Spec到到Process Parameter1. Basic concept of SPCnVariationnControl (Stability)-Statistical stable status-Process performance can be predictablenCapabilitynOver-adjustmentSPC -品管七大手法nHistogramn

2、Check SheetnParetonCause and effect diagramnDefect concentration diagramnScatter diagramnControl chart Basic concept of SPCn检定是否为常态分配n管制图的中心线X-barn管制图的管制界限(信赖水平,信赖区间)nControl Limits =信赖区间 1.集中趋势（通常以X bar作代表） 2.离中趋势（通常以 作代表） 3.信赖水平-被含盖在特定范围内的机率 信赖水平-被含盖在特定范围内的机率X barX bar 信赖水平信赖水平, ,信赖区间信赖区间 信赖水平信赖水平

3、 信赖区间信赖区间n 90% 1.645 95% 1.96 99% 2.575 99.73% 3 n 99.94% 3.5n 99.99% 3.9 n 99.994% 3.99信赖水平信赖水平, ,信赖区间信赖区间,P, Ppk/Cpk信赖水平信赖水平P信赖区间信赖区间Ppk/Cpk90%10%1.6450.54895%5%1.960.65399%1%2.575 0.85899.73%0.27% 3 199.94%0.06%3.51.16799.99%100ppm3.91.399.994%60ppm 3.991.33 Z Basic concept of SPCn用管制图判别special c

4、ause的准则n超过管制界限n连续七点向上n连续七点向下n连续七点向单边n不随机分布 Basic concept of SPCnStatistical stable = no special cause = Under control = process performance can be predictable当制程达到Statistical stable时才可计算Cpk Stable Process Unstable Process Basic concept of SPCnOver-adjustment :当对common cause所造成的变异都采取措施调整制程时,等于将一个spec

5、ial cause加入己稳定的制程。使原本稳定的制程变成不稳定。 Basic concept of SPCnPpknCanCpnCpk Basic concept of SPCnCa : Sensitive to Specification targetnCp : Sensitive to variation(spread)nCpk : Sensitive to both, capability index for stable process Only common cause variation includednPpk : Performance index Both common ca

6、use and special cause variation includednCp CpkBasic concept of SPCnVariation :制程输出不可避免的差异nInherent Variation (固有变异):由common cause所造成的变异n= R bar / d2nTotal Variation :由common cause and special cause所造成的变异nPpknCpk Cpm 管制图种类包括管制图种类包括n计量值管制图计量值管制图n计数值管制图计数值管制图Data的种类n计量值计量值(location & spread)n计数值计数

7、值计量值管制图计量值管制图nX-Bar R ChartnX-median R ChartnX-Bar S ChartnX-Rm Chart计数值管制图种类包括计数值管制图种类包括 nPn Pnn Cn U 管制图的目的n预防不良品产出n判定制程是否有非机遇因子造成的变异n去除非机遇因子造成的变异n减小制程的变异n改善制程n判定制程是否稳定n制程能力分析n100%检验还需耍做管制图吗?n如何做?特殊应用管制图特殊应用管制图nCUSUMcumulative-Sum Control Chart)累积和管制图nEWMAexponentially Weighted Moving Average Cont

8、rol Chart)指数加权移勋平均管制图nEVOP(Evolutionary Operation)-Part Average Test渐进操作法管制图nAcceptance Control Chart允收管制图nModified Control Limits Control Chart修正界限管制图nShort Run短制程管制图Short Run短制程管制图 Guard Band Limit-GRR Guard Band Limit-Cpk MSAnMeasurement System AnalysisStatistic techniqueMS ControlMSA MSA GRR v.

9、s. CPAccuracy & Precision MSAn计量值计量值 Location - Bias, Linearity, Stability Spread Repeatability, Reproducibility(GRR) Range Method Average Range Method Average Range Method(Within Part Variation) ANOVA DOEn计数值计数值-Short Method -Long Method Bias Stability Linearity Repeatability Reproducibility GR

10、R-Average-Range Methodn%GRR = % R&R = 100(R&R/TV)nTV2 = R&R2 + PV2nR&R2 = EV2 + AV2 TV2EV2AV2PV2GRR-Range MethodGRR-Average-Range MethodANOVA MethodMSA timing & applicationnMSA / APQP/ Product RealizationnMSA / FMEA MSA的目的的目的n何种情况可不必做何种情况可不必做GRR ?nCp is good, not use for process

11、measurement, C/I not required?n只只做做GRR,不不做做Bias, Linearity, Stability可以吗可以吗?MSA for measurement cant be repeatednThe inability to test the same unit repeatedly is a major obstacle to obtaining an estimate of pure measurement error.nDestructive testingnMeasuring a temperature, viscositynSamples obtai

12、ned from the product stream should be as closed together as possiblenWith film, one might prefer adjacent samples collected in the machine direction rather than from different positions across the webnObtain pairs of samples that are as homogeneous as possible within each pair, each pair may be test

13、ed and the difference in the paired readings taken to obtain an estimate of the variation of the measurement processData Categories & ResolutionData Categories & ResolutionData Categories & ResolutionData Categories & ResolutionData Categories & ResolutionData Categories & Re

14、solutionData Categories & ResolutionData Categories & Resolution PT RationPrecision Tolerance RationThe ratio of parameter tolerance to measurement system repeatabilitynPT=Tolerance /EVMSA ResultnGage resolution to spec tolerancenGage resolution to Process variationnBiasnStabilitynLinearitynR&RWhen should MSA be conducted in APQP/Product Realization/Product Life cyclenProduct design reviewnProcess design re