6160sigma160bb黑帶培訓資料-160160booster_wk1_03_msa(編輯修改稿)
2025-07-03 21:52 本頁面
【文章內(nèi)容簡介】 ‖ is extremely desirable. It is better that the operator not know that the part being measured is part of a special test. At a minimum, they should not know which of the test parts they are currently measuring. ?You analyze the variation in the study results to determine how much of it es from differences in the operators, techniques, or the units themselves. 18 How a Gage Ramp。R Study Works ?Select units or items for measuring that represent the full range of variation typically seen in the process ? Measurement systems are often more accurate in some parts of the range than in others, so you need to test them over the full range ?Have each operator measure those items repeatedly ? In order to use Minitab to analyze the results, each operator must measure each unit the same number of times ? It is extremely desirable to randomize the order of the units and not let the operator know which unit is being measured ?Minitab looks at the total variation in the items or units measured 19 How a Gage Ramp。R Study Works, cont. ? Minitab then estimates the proportion of the total variation that is due to 1. Parttopart variation: physical or actual differences in the units being measured 2. Repeatability: Inconsistency in how a given person takes the measurement (lots of inconsistency = high variation = low repeatability) 3. Reproducibility: Inconsistency in how different people take the measurement (lots of inconsistency = high variation = low reproducibility) 4. Operatorpart interaction: An interaction that causes people to measure different items in different ways (., people of a particular height may have trouble measuring certain parts because of lighting, perspective, etc.) ? If there is excessive variation in repeatability or reproducibility (relative to parttopart variation), you must take action to fix or improve the measurement process ? The goal is to develop a measurement system that is adequate for your needs 20 Adequate vs. Inadequate Measurement Systems Adequate Inadequate ? Most of the variation is accounted for by physical or actual differences between the units – What Minitab calls parttopart variation will be relatively large – All other sources of variation will be small – You can have higher confidence that actions you take in response to data are based on reality ? The measurement system has sufficient precision to distinguish at least five groups or ―categories‖ of measurements ? Variation in how the measurements are taken is high You can’t tell if differences between units are due to the way they were measured, or are true differences You can’t trust your data and therefore shouldn’t react to perceived patterns, special causes, etc.—they may be false signals ? The measurements fall into less than five categories – – 21 Measurement System Indices ? %Ramp。R ? Describes the variation of the measurement system in parison to the part variation of the process ? ? %P/T ? Describes the variation of the measurement system in parison to the part tolerances ? t ot als y s t e mtm e as ur e m e nSSRR _amp。% ?T ol e r anc e sSTP s y s t e mtm e as ur e m e n _*?U
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