【正文】 f the lot means, ? = the standard deviation of the lot means, where xixSxxxNiiN? ??1 ? ?Sx xNxiiN????? 211UCL x S x? ? 3CL x?LC L x S x? ? 3Compute the control limits using: 174。 Materials Quality PCS Training Rev 3 May 21 2022 35 Caution When Using MR Method ? If there is autocorrelation, MR(Summary Stat) will underestimate the true process variation amp。 Materials Quality PCS Training Rev 3 May 21 2022 34 T i m eDataC o ns e c u t i v e l ot sa re v e ry s i mi l a rLo t s f a r a pa rt ma ybe v e ry dif f e re nt? Timerelated condition where consecutive data values are correlated (. dependent) 連貫的數(shù)據(jù)有關(guān)連性 ? Data values collected nearby in time are very similar 鄰近時(shí)間的數(shù)據(jù)非常相似 ? Data values collected far apart in time may be very different 較久時(shí)間的數(shù)據(jù)差異大 ? Tend to drift over time。 the number of units containing undissolved flux were recorded over several lots. Make a p Chart for Undissolved Flux Interpret the control chart 174。 Materials Quality PCS Training Rev 3 May 21 2022 31 Open the dataset . ? Select Control Chart from the Graph menu. ? Select % Defectives as the Process variable. ? Select Lot as the Sample Label variable. Verify option settings. ? Chart Type is “IR”. ? Individual Measurement box is selected. ? Moving Range box is not selected. ? Ksigma is selected, and K = 3. ? Range Span = 2. Click on OK. Example of Computing Control Limits for p Chart 174。LCL (p) = p ? When LCL 0, put LCL = 0 or N/A ? Draw the control limits on p chart 174。UCL(p) = p + 187。 Materials Quality PCS Training Rev 3 May 21 2022 29 Computing Control Limits for p Chart with MRMethod ? Obtain at least k = 30 subgroups or lots. Data collected in of units inspected amp。 Materials Quality PCS Training Rev 3 May 21 2022 27 Control Charts For Attributes C o n trol C h art Sy m b o l D es crip tionp C h art p % D efe cti ven p ch art np d efe cti ve174。 Materials Quality PCS Training Rev 3 May 21 2022 25 Interpretation of X S Chart Some special causes of outofcontrol for ? X Chart – Changes in machine setting or adjustment – 參數(shù)設(shè)定被調(diào)整 – MStoMS technique inconsistent – Changes in material – 材料變化 ? S Chart – Machine in need of repair or adjustment – 機(jī)器須維修 – New Mses – Materials are not uniform – 材料一致性不夠 174。 Materials Quality PCS Training Rev 3 May 21 2022 23 WARNINGS: Group / Summary will sort the new table in alphabetical order of the grouping variable. Control charts must always be plotted in time order. Therefore, if the summary table is not in time order, you will have to sort the table in correct time order before making the control chart. Example of Computing Control Limits for X S Chart using JMP LCL (S) = 0 174。 ranges. ? Select Control Chart from the Graph menu. ? Select Mean(thickness) amp。 select Mean from the Statistics menu. Then, highlight Thickness amp。 Materials Quality PCS Training Rev 3 May 21 2022 21 Observations Mean Moving Range S. D. Moving Range Subgroup 1 2 3 4 5 (X bar) (MRX ) (S) (MR S ) 1 2 3 : : 30 Average ? X Chart UCL (X) = X + = + () = CL (X) = X = LCL (X) = X = () = Example of Computing Control Limits for X S Chart ? S Chart UCL (S) = S + = + () = CL (S) = S = LCL (S) = S = () = 174。CL (S) = S 187。LCL (X) = X = = = Computing Control limits for X S Chart S Chart 187。UCL (X) = X + 187。 Materials Quality PCS Training Rev 3 May 21 2022 19 Computing Control limits for X S Chart ? Compute the Overall Mean, X = (X1 + X2 + X3 ... + Xk) / k ? Compute the Average of Range, S = (S1 + S2 + S3 ... + Sk) / k ? Compute the Average of Moving Range for the mean, MRX = (MRX2 + MRX3 + MRX4 ... + MRXk) / (k 1) ? Compute the Average of Moving Range for the range, MRS = (MRS2 + MRS3 + MRS4 ... + MRSk) / (k 1) = 174。顯示抽樣標(biāo)準(zhǔn)差的改變 174。以抽樣的標(biāo)準(zhǔn)差描點(diǎn) 187。顯示抽樣平均值的改變 – S Chart 187。以抽樣的平均值描點(diǎn) 187。 Materials Quality PCS Training Rev 3 May 21 2022 17 X S Chart Concept Consists of Two Portions: – X Chart 187。 Standard Deviation) Chart? 為什麼要使用移動(dòng)全距方法 ? ? Most batch production processes have a larger runtorun variation than withinrun variation 批量性生產(chǎn)時(shí) ,子群組間的變異大多會(huì)大於子群組內(nèi)的變異 ? Traditional control chart formulas developed in the 20?s by Walter Shewhart considerably underestimate control limits, . too narrow 傳統(tǒng)的方法將使管制界限太窄 174。 Materials Quality PCS Training Rev 3 May 21 2022 15 Why MR Method is used to determine Control Limits for Mean amp。 Materials Quality PCS Training Rev 3 May 21 2022 14 Control Chart When to Use (Guidelines only)? XS when subgrouping of samples or (MeanStandard Deviation) Chart measurements is applicable n = 10 n=10 X when subgrouping is not applicable (Individual) due to single unit reading may take Chart a long time, unit reading is extremely expensive, etc. when it39。 Materials Quality PCS Training Rev 3 May 21 2022 13 Control Chart Classifications 類型 Classifications of control charts are depending on the type of data 依數(shù)據(jù)型態(tài)可分類為 : ? Variables data 計(jì)量型數(shù)據(jù) – A characteristic measured on a continuous scale resulting in a numerical value 特性 : 連續(xù)性 ,可量測 ,有小數(shù)點(diǎn) – Examples: Void Size, Bond Pull Strength, Coplanarity, Ball Height, etc. 如尺寸 ,推拉力 ,平面度 ,高度 ? Attributes data 計(jì)數(shù)型數(shù)據(jù) – A characteristic measured by of conforming amp。 Materials Quality PCS Training Rev 3 May 21 2022 12 ? Validate the puted control limits against data collected by replotting the control chart with data amp。 plot them on the trend