spcattributecontrolcharts-資料下載頁
2025-02-17 21:42本頁面
【正文】 artExample 3: c and u ChartsMiniTab’s Stat ? Control Charts ? USeagate Confidential 45Attribute Control ChartExample 3: c and u ChartsSeagate Confidential 46Attribute Control Chartu (or c) Chart vs p (np) ChartThe u (or c) chart offers the following advantages:l More informative as the type of nonconformity is noted.l Facilitates Pareto analysis.l Facilitates Cause Effect Analysis.Seagate Confidential 47Attribute Control Chartl c Chart232。 Measures the total number of defects in a subgroup 252。 The subgroup size can be 1 unit of product if we expect to have a relatively large number of defects/unit232。 Requires a constant subgroup size? u Chart232。 Measures the number of defects/unit of product (dpu) 232。 The subgroup size can be constant or variable? p Chart232。 Measures the proportion of defective units in a subgroup232。 The subgroup size can be constant or variable? np Chart232。 Measures the number of defective items in a subgroup232。 Requires a constant subgroup sizeSelecting the Appropriate ChartSeagate Confidential 48Attribute Control ChartExercise 1l Strength of 5 test pieces sampled every hourl Number of defectives in 100 partsl Number of solder defects in a printed circuit board assemblyl Diameter of 40 units of products sampled every dayl Percent defective of a lot produced in every 30min periodl Surface defects of surface area of varying sizesl In a maintenance group dealing with repair work, the number of maintenance requests that require a second call to plete the repair every weekSeagate Confidential 49Attribute Control ChartTest for InstabilitySuitable for all chartsSuitable only for XChart_Seagate Confidential 50Attribute Control ChartTests for InstabilityCAUTION : Do not apply “tests” blindlyl Not every “test” is relevant for all chartsl Excessive number of “tests” ? Increased ?errorl Nature of applicationSeagate Confidential 51Attribute Control ChartVariables vs Attributes Chartsl Attributes Control Charts facilitate monitoring of more than 1 quality characteristics.l Variables Control Charts provide leading indicators of trouble。 Attributes Control Charts react after the process has actually produced bad parts.l For a specified level of protection against process drift, Variables Control Charts require a smaller sample size.Seagate Confidential 52Attribute Control ChartEnd of TopicWhat Question Do You HaveSeagate Confidential 53Attribute Control ChartReading ReferenceIntroduction to Statistical Quality Control, Douglas C. Montgomery, John Wiley Sons, ISBN 0471303534 Seagate Confidential 54Attribute Control Chart謝謝觀看 /歡迎下載BY FAITH I MEAN A VISION OF GOOD ONE CHERISHES AND THE ENTHUSIASM THAT PUSHES ONE TO SEEK ITS FULFILLMENT REGARDLESS OF OBSTACLES. BY FAITH I BY FAIT
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