【正文】 ve Characterizations of Measurement System: 2. Width Variation: Repeatability。 Linearity Stability(Alias: Drift): Stability is the total variation in the measurements obtained with a measurement system on the same master or parts when measuring a single characteristic over an extended time period. A stable measurement process is in statistical control with respect to location. Stability Introduction: Where does the variation of measurement system e from? ? The Five Characterizations of Measurement System: 1. Location Variation: Bias。 Linearity Bias is the difference between the observed average of measurements and a reference value. Bias is often referred to as accuracy. It is a systematic error ponent of the measurement system Introduction: Where does the variation of measurement system e from? ? The Five Characterizations of Measurement System: 1. Location Variation: Bias。 TS16949 requirements, all measurement system which were mentioned in Quality Plan should be conducted Measurement System Analysis. MSA Requirement Introduction: The category of Measurement System ? Most industrial measurement system can be divided two categories, one is variable measurement system, another is attribute measurement system. An attribute gage cannot indicate how good or how bad a part is , but only indicates that the part is accepted or rejected. The most mon of these is a Go/Nogo gage. Variable Gage Attribute Gage (Go/Nogo Gage) Introduction: What is a measurement process Operation Output Input General Process Measurement Analysis Value Decision Process to be Managed Measurement Process Measurement: The assignment of a numerical value to material things to represent the relations among them with respect to a particular process. Measurement Process: The process of assigning the numerical value to material things. Introduction: What are the variations of measurement process Introduction: What are the variations of measurement process Measurement(Observed) Value = Actual Value + Variance of The Measurement System 2 σobs = 2 σ actual + σ variance of the measurement system 2 Introduction: Where does the variation of measurement system e from? ? The Five Characterizations of Measurement System: 1. Location Variation: Bias。 Training Material for MEASUREMENT SYSTEM ANALYSIS Contents : 1) INTRODUCTION FOR MEASUREMENT SYSTEM ANALYSIS 2) GENERAL METHODS ILLUSTRATION FOR MEASUREMENT SYSTEM ANALYSIS 1) VARIABLE GAGE ANALYSIS METHOD 1) THE AVERAGERANGE METHOD 2) THE ANOVA METHOD 1) ATTRIBUTE GAGE ANALYSIS METHOD 1) SHORT METHOD 2) HYPOTHESIS TEST ANALYSIS 3) SIGNAL DETECTION THEORY 4) LONG METHOD 3) ACCEPTABILITY CRITERIA 4) CONCLUSION 5) FOUR METHODS COMPARISON Introduction: Basic requirements by QS9000 amp。 TS16949 ? Base on QS9000 amp。 Stability。 Stability。 Stability。 Reproducibility。R Repeatability is the variation in measurements obtained with one measurement instrument when used several times while measuring the identical characteristic on the same part by an appraiser. It is a Withinsystem variation, monly referred to as Variation. Repeatability Introduction: Where does the variation of measurement system e from? ? The Five Characterizations of Measurement System: 2. Width Variation: Repeatability。 Gage Ramp。 Reproducibility。R Gage Ramp。R (%Ramp。R is the basis for making a judgment of whether the measurement system is good enough to measure the process. Analysis Techniques: ? Currently there are three techniques for variable measurement system and four techniques for attribute measurement system analysis were remended by AIAG MSA Reference Manual. ? Range Method ? Average Range Method ? ANOVA ? Short Method ? Long Method ? Hypothesis Test Analyses ? Signal Detection Theory ? Followings are some practical examples to illustrate how to perform four methods respectively. Variable Gage Attribute Gage Analysis Techniques: Preparation before MSA 1. The approach to be used should be planned. 2. The number of appraisers, number of sample parts, and number of repeat readings should be determined in advance. 3. The appraisers should be selected form those who normally operate the instrument. 4. The sample parts must be selected from the process and represent its entire operating range. 5. The instrument must have a discrimination that allows at least onetenth of the expected process variation of the characteristic to be read directly. 6. The measurement procedure should be defined in advance to ensure the consistent measuring method. Analysis Techniques: Variable Gage Analysis 1. General Gage Ramp。R study: 1. Verify calibration of measurement equipment to be studied. 2. Obtain a sample of parts that represent the actual or expected range of process variation. 3. Add a concealed mark to each identifying the units as numbers 1 through 10. It is critical that you can identify which unit is which. At the same time it is detrimental if the participants in the study can tell one unit from the other (may bias their measurement should they recall how it measured previously). 4. Request 3 appraisers. Refer to these appraisers as a A, B, and C appraisers. If the measurement will be done repetitively such as in a production environment, it is preferable to use the actual appraiser that will be performing the measurement. For extreme cases, a minimum of two appraisers can be used, but this is strongly discouraged as a less accurate estimate of measurement variation will result. 5. Let appraiser A measure 10 parts in a random order while you record the data noting the concealed marking. Let appraisers B and C