10-Gage(测量).ppt

Six Sigma Champion Training Measurement Systems Analysis Champion Training Learning Objectives Understand the language of Measurement Show the importance of Measurement Walk away knowing how to perform a Gage RR and how to interpret results Share some lessons learned Since Measurement systems represent a sub-process within a process... Sources of Measurement Variation Possible Sources of Process Variation Knowledge to be obtained How big is the measurement error? What are the sources of measurement error? Is the gage stable over time? Is the gage capable for this process? How do we improve the measurement system? Sources of Variation Effects of Measurement Error Work Around Gage Error Terminology Location related terms: True value Bias Linearity Stability (over time) Variation related terms Repeatability Reproducibility Linearity True value: Theoretically correct value – unknown and unknowable Reference standards NIST standards Bias Distance between average value of all measurements and true value Amount gage is consistently off target Systematic error or offset  Linearity Difference in the accuracy values of a gage through the expected operating range of the gage Stability The distribution of measurements remains constant and predictable over time for both mean and standard deviation Total variation in the measurements obtained with a gage, on the same master or master parts, when measuring a single characteristic over an extended time period. Evaluated using a trend chart or multiple measurement analysis studies over time  Total variation in the measurement system Measure of natural variation of repeated measurements Terms: Random Error, Spread, Test/Retest error Repeatability and Reproducibility Repeatability The inherent variability of the measurement system Variation in measurements obtained with a gage when used several times by one operator while measuring a characteristic on one part. Estimated by the pooled standard deviation of the distribut