On the other hand, the reproducibility is the uncertainty among operators for measuring the same part. Since part and operator are fixed, the variance component for the repeatability is the random error, s2. Row Punch OperA OperB OperC Row Punch OperA OperB OperCĤ A statistical Model for Describing the Gage R&R Studyĥ The Repeatability is the uncertainty among replications of m measurements of a given part made by the an operator. Each operator measured each punch three time. Ten parts with steel punches are randomly selected. Three operators were randomly selected for the the study. Pat-to-Part Variation Variation due to Gage Overall Variation Repeatability Measurement System Variation Operators Variation due to Operators Reproducibility Operator by Partģ Case Study (Data are from Vardeman & Jobe (1999):Ī study was conducted to investigate the precision of measuring the heights of 10 steel punches (in 10-3 inches) using a certain micrometer caliper. The reproducibility component can be further broken down into its operator, and operator by part, components. The overall variation is broken down into three categories: part-to-part, repeatability, and reproducibility.
The variability among operators is the Reproducibility.Ģ Gage repeatability and reproducibility studies determine how much of your observed process variation is due to measurement system variation. The variation among the m replications of the given parts measured by the same operation is the Repeatability of the gage. Each of the J operators is asked to measure the characteristic of each of the I parts for r times (repeatedly measure the same part r times). I parts are randomly chosen and prepared for the study. A gage or a certain instrument is chosen as the measuring device. A typical gage R&R study is conducted as the following: A quality characteristic of an object of interest (could be parts, or any well defined experimental units for the study) is selected for the study. The Gage R&R analysis is a technique to quantify each component of the variation so that we will be able to determine what proportion of variability is due to operators, and what is due to the parts. The precision of the measurements using this gage involves at least two major components: the systematic difference among operators and the differences among parts. The name of this technique originated from the operation of a gage by different operators for measuring a collection of parts. This is a technique to measure the precision of gages and other measurement systems. 1 Module 13: Gage R&R Analysis – Analysis of Repeatability and Reproducibility
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