SPC統(tǒng)計(jì)過程控制培訓(xùn)教材(共114頁).ppt

1、1統(tǒng)計(jì)過統(tǒng)計(jì)過程控制程控制工作坊工作坊 SPC Work Shopv精益管理顧問公司 -企業(yè)管理的好幫手 2基本統(tǒng)計(jì)概念 Basic SPC Concept3統(tǒng)計(jì)學(xué)統(tǒng)計(jì)學(xué) (Statistics) v收集、 整理、展示 、分析 、解析統(tǒng)計(jì)資料Collect, collate, display, analysis, explain of datav由樣本推論母體/群體From sample to project the populationv能在不確定情況下作決策 Decision with uncertaintyv是一門科學(xué)方法、決策工具Scientific and decision tool

2、基本統(tǒng)計(jì)概念 Basic SPC Concept抽樣推論x4統(tǒng)計(jì)量 Statistical ValuevR 全距 (range)v 算術(shù)平均數(shù) (arithmetic mean)vMd 中位數(shù) (median)vMo 眾數(shù) (mode)v2 方差/變異 (variance)v標(biāo)準(zhǔn)差 (standard deviation)基本統(tǒng)計(jì)概念Basic SPC Concept)(x5vR 全距 (range)R = Xmax - Xminv 算術(shù)平均數(shù) (arithmetic mean)基本統(tǒng)計(jì)概念Basic SPC Conceptnxfxniii1)(x6vMd 中位數(shù) (median)順序數(shù)列中的

3、中心項(xiàng)的數(shù)值The medial number in the seriesvMo 眾數(shù) (mode)資料中出現(xiàn)最多的數(shù)值The number with highest frequency基本統(tǒng)計(jì)概念Basic SPC Concept7v2 方差/變異 (variance)基本統(tǒng)計(jì)概念Basic SPC Concept)xx(.)xx()xx(1n11n)xx(f2n2221n1i2ii21n)xx(.)xx()xx(n1n)xx(f2n2221n1i2ii2n8v標(biāo)準(zhǔn)差 (standard deviation)基本統(tǒng)計(jì)概念Basic SPC Concept2n2221n1i2iin)xx(.)

4、xx()xx(n1n)xx(f2n2221n1i2ii1n)xx(.)xx()xx(1n11n)xx(f9例：Case1, 1, 2, 3, 4, 6, 11 R = 10 = 4 Md = 3 Mo= 1 n 2 = 10.86 n-12 = 12.67 n= 3.29 n-1= 3.56 基本統(tǒng)計(jì)概念Basic SPC Conceptx10數(shù)列 Series： 12, 11, 12, 13, 18, 30, 24, 9請(qǐng)計(jì)算下列統(tǒng)計(jì)量 Calculate the following:vR v vMd vMo vn 2 = n-12 =vn= n-1=練習(xí)Exercisex11數(shù)據(jù)的收集與整

5、理Data Collection and Collation分析分析測測試試行行動(dòng)動(dòng)ActionTestAnalysis數(shù)數(shù)據(jù)據(jù)Data結(jié)結(jié)Conclusion樣樣本本Sample群體群體PopulationSampling抽抽 樣樣12數(shù)據(jù)收集 Data Collection33333031313128292934273327302933312827343326323532263228342828293028293432303128302732293026302831303132292527293027303329292926313213數(shù)據(jù)整理 Data Collate - 次數(shù)分配 Fr

6、equency Distribution數(shù)數(shù)值值 Value 次次數(shù)數(shù)劃劃記記 Freq Marks 次次數(shù)數(shù) Freq 25 X 1 26 XX 4 27 XXXXXX 6 28 XXXXXXXX 8 29 XXXXXXXXXX 10 30 XXXXXXXXXX 10 31 XXXXXXXX 8 32 XXXXXX 6 33 XXXXXX 6 34 XXXX 4 35 X 1 14直方圖 (Histogram)15分布曲線 Distribution Curve16正態(tài)(常態(tài))分布的曲線圖Normal Distribution Curve0.4)(zf0.30.20.1-2.5-2.0-1.5

7、-1.0-0.500.51.01.52.02.522121)(zezf1117正態(tài)分布的性質(zhì)Nature of Normal Distribution- 3 - 2 -1 1 2 3 機(jī)會(huì)率機(jī)會(huì)率 Probaility 0.67 50.00 % 1 68.26 % 1.96 95.00 % 2 95.45 % 2.58 99.00 % 3 99.73 % 18數(shù)據(jù) Data 直方圖Histogram 分布曲線 Distributionxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

8、xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx33333031313128292934273327302933312827343326323532263228342828293028293432303128302732293026302831303132292527293027303329292926313219直方圖 Histogram 分布

9、 Distribution01020304050525 530 535540 545 550555 560 565570 575 58001020304050-0.75-0.7-0.65-0.6-0.55-0.5-0.45-0.4正常型正常型Normal20直方圖 Histogram 分布 Distribution02468101211811912012112212312412512612712812901020304016171819202122232425偏向型偏向型 Bias21直方圖Histogram 分布Distribution02468100.640.660.680.70.720.

10、740.76051015200.530.550.570.590.610.630.650.670.690.710.730.750.770.790.810.83孤島型孤島型 Island22過程變差Process Variation23輸入 (材料)Input (Material)人 Man方法 Method過程 (生產(chǎn)/裝配)Process輸出(產(chǎn)品)Output (Product)反饋(測量/檢驗(yàn))Feedback (Test/Insp.)測量系統(tǒng)MSA)材料Material過程變差 Process Variation機(jī)器 Machine 24過程變差 Process Variationv輸入

11、材料 Material Input不同批次之間的差異 Lot to Lot Variation批次內(nèi)的差異 Within Lot Variation隨時(shí)間產(chǎn)生的差異 Variation in Time Series隨環(huán)境而產(chǎn)生的差異 Variation due to Environment25過程變差 Process Variationv生產(chǎn)/裝配 Production/ Assembly設(shè)備及工裝夾具的差異 Equipment and Tooling Variation隨時(shí)間而產(chǎn)生的磨損，漂移等 Aging and Shift by time操作工之間的差異(如手工操作的過程)Variati

12、on between Operators ( Manual Work)設(shè)置的差異 Different Setup環(huán)境的差異Different Environments26過程變差 Process Variationv輸出產(chǎn)品 Output Product輸出的產(chǎn)品隨時(shí)間而產(chǎn)生的變化Product Variation by time series輸出的產(chǎn)品隨環(huán)境而產(chǎn)生的變化Product Variation due to environment27過程變差 Process Variationv反饋 - 測量 Feedback- Measurement由于測量用于過程中的所有組成部分，測量的變差會(huì)

13、對(duì)過程的各個(gè)階段產(chǎn)生影響Measurements are part of the process, variation in the measurement can affect the process in various stagesv偏倚 Biasv穩(wěn)定性 Stabilityv重復(fù)性 Repeatabilityv再現(xiàn)性 Reproducibilityv分辨率 Resolution28持續(xù)改進(jìn)過程循環(huán)的各個(gè)階段持續(xù)改進(jìn)過程循環(huán)的各個(gè)階段2. 維護(hù)過程維護(hù)過程 監(jiān)控過程性能查找偏差的特殊原因並採取措施 3. 改進(jìn)過程改進(jìn)過程. 改變過程從而更好地理解普通原因變差 減少普通原因變差分析過程分析

14、過程本過程應(yīng)做些什麼?會(huì)出現(xiàn)什麼錯(cuò)誤?本過程正在做什麼?達(dá)到統(tǒng)計(jì)控制狀態(tài)?確定能力計(jì)劃實(shí)施措施研究計(jì)劃措施實(shí)施研究計(jì)劃實(shí)施措施研究29過程變差 Process Variation范圍范圍范圍范圍每件產(chǎn)品的尺寸與別的不同Each product dimension has differences SPEC30過程變差 Process Variation范圍范圍范圍但它們形成一個(gè)模型，若穩(wěn)定，可以描述為一個(gè)分布The data are grouped to form the model. If stable, it can be descried as the distribution.31過程變

15、差 Process Variation分布可以通用過以下因素來加以區(qū)分Distribution can be descried with various elements或這些因數(shù)的組合 Or the combination of these elements范圍范圍范圍位置位置 Position分布分布寬寬度置度置 Spread形形狀狀 Form/ Shape32過程變差 Process Variation預(yù)測Forecast范圍 SPEC時(shí)間 Time如果只存在如果只存在變變差的普通原因，差的普通原因，隨隨著著時(shí)間時(shí)間的推移，的推移，過過程的程的輸輸出出形成一形成一個(gè)穩(wěn)個(gè)穩(wěn)定的分布定的分布

16、并并可可預(yù)測預(yù)測If there are only the common causes, and move in time series, the process outputs are predictable with stable distribution 目標(biāo)直線Target Line33過程變差 Process Variation目標(biāo)直線 Target Line預(yù)測 Forecast范圍 Spec時(shí)間 Time如果存在如果存在變變差的特殊原因，差的特殊原因，隨隨著著時(shí)間時(shí)間的推的推移，移，過過程的程的輸輸出不出不穩(wěn)穩(wěn)定定If the special cause is in the va

17、riation, in time series, the process become unstable？34過程控制和過程能力Process Control and Process Capability過過程控制程控制 Control Process 受控 In Control(消除了特殊原因)Eliminate the Special Cause時(shí)間 Time范圍 SPEC不受制 Out Of Control(存在特殊原因) with Special Cause35過程變差 Process VariationvDistribution can be described by:uLocati

18、on (typical value)位置 (典型值) uSpread 分布寬度 uShape(pattern of variation)形狀 (變差的模式) LSLUSLTypical value典型值 SpreadSpread分布分布 36過程變差 Process Variationv過程的變差分兩個(gè)類型 Two Categories特殊原因造成的變差 Special Causes普通原因造成的變差 Common Causes37過程變差 Process Variationv普通原因變差 Common Causes in Variation影響過程中每個(gè)單位 affect each unit

19、 in the process是由所有不可分派的小變差源組成 Formed by various variation sources; and但遵循一個(gè)分布 follow a particular distribution通常需要采取系統(tǒng)措施來減小Use system corrective actions to reduce在控制圖上表現(xiàn)為隨機(jī)性random point in the control chartIf only common cause, the process output of a process is Predictable如只有普遍原因，輸出是可預(yù)計(jì)的過程。 38過程變差

20、 Process Variationv特殊原因變差 Special Causes in Variation間斷的，偶然的，通常是不可預(yù)測的和不穩(wěn)定的變差Discontinued, accidental, unpredictable and unstable非隨機(jī)的圖案 Non random pattern是由可分派的變差源造成該變差源可以被糾正Can be corrected, the cause is from the particular source39過程變差 Process Variationv工業(yè)經(jīng)驗(yàn)建議為：Industrial Experience局部措施 Local actio

21、n通常用來消除變差的特殊原因Usually required to eliminate special causes of variation通常由與過程直接相關(guān)的人員實(shí)施 Usually taken by people close to the process大約可糾正15%的過程問題 Only 15% of process problem can be corrected40過程變差 Process Variationv工業(yè)經(jīng)驗(yàn)建議為：Industrial Experience對(duì)系統(tǒng)采取措施 Actions on the system通常用來消除變差的普通原因 Usually requir

22、ed to eliminate / or reduce common causes of variation, and be taken by management大約可糾正85%的過程問題 About 85% of process problem can be corrected41過程控制和過程能力Process Control and Process Capability過程能力 Process Capability規(guī)范上限受控且有能力符合規(guī)范(普通原因造成特變差)Control and capable to fit the spec (variation due to Normal C

23、ause)受控但沒有能力符合規(guī)范 Control but without capability to fit the spec(普通原因造成變差太大) Large variation due to Normal Cause Spec時(shí)間 Time42過程控制和過程能力Process Control and Process Capability每個(gè)過程可以分類如下：Each process can be categorized as: Control or out of control ? 受控或不受控? Fit the customer requirements ? 是否有滿足客戶要求 ? M

24、eeting requirement滿足要求In Control受控Not In Control 不受控Acceptance符合Case 1 第1類Case 3 第3類Not Acceptance不符合Case 2 第2類Case 4 第4類43過程控制和過程能力第1類 (符合要求，受控) Case 1 (Accept, In Control) 是理想狀況。為持續(xù)改進(jìn)可能需要進(jìn)一步減小變差I(lǐng)deal Status, to reduce variation for continuous improvement. 第2類 (不符合要求，受控) Case 2 (Not Accept, In Cont

25、rol)存在過大的普通原因變差 with large variation from normal cause 短期內(nèi)，進(jìn)行100%檢測以保護(hù)客戶不受影響In short term, go for 100% inspection to reduce the effect for customer 必須進(jìn)行持續(xù)改善以減少普通原因的變差 Must go for continuous improvement to eliminate the effect from common cause44過程控制和過程能力Process Control and Process Capability第3類類 (符合

26、要求，不受控符合要求，不受控) Case 3. Accept but OUT of controlv有相對(duì)較小的普通原因及特殊原因變差With less normal and special causes v如果存在的特殊原因已經(jīng)明確但消除具影響可能不大經(jīng)濟(jì)，客戶可能接受這種過程狀況If the special causes are known but the cost may be high to eliminate them, customer may accept this process status.45過程控制和過程能力第4 4類類 ( (不符合要求，不受控不符合要求，不受控) )

27、 Case 4 ( Not Accept, OUT of Control)v存在過大的普通原因及特殊原因的變差Larger Normal and special causes in the variationv需要進(jìn)行100%檢測以保護(hù)客戶利益 必須采取緊急措施使過程穩(wěn)定，并減小變差Must go for contingency/ containment actions to stable the process and reduce variations, 100% inspection to protect customer46過程控制和過程能力v判斷一個(gè)過程是否滿足規(guī)格要求： Judge

28、 the process can fit the spec requirementsCapability Index 能力指能力指數(shù)數(shù) - Cpk (For stable Process only 只用於穩(wěn)定過程)Performance Index 性能指性能指數(shù)數(shù) Ppkv判斷一個(gè) 過程是受控還是不受控用：Judge the process is in control or out of control控制控制圖圖 Control Charts47控制圖 Control Charts 為為判判斷斷制程制程變變差的差的普通原因或特殊原普通原因或特殊原因因的主要的主要統(tǒng)計(jì)統(tǒng)計(jì)分析工具分析工具To

29、 judge the process To judge the process variation with variation with COMMON or COMMON or SPECIALSPECIAL cause as the major cause as the major statistical analysis toolstatistical analysis tool48基本概念 Basic Conceptv控制圖中包括三條線 3 lines in Control Chart控制上限 (Upper Control Limit; UCL)中心線 (Center Line; CL)

30、控制下限 (Lower Control Limit; LCL)UCLCLLCL49控制圖的種類 Type of Control Charts v計(jì)量型數(shù)據(jù)的控制圖 Variable Control ChartsXbar-RXbar-SX-MRv計(jì)數(shù)型數(shù)據(jù)的控制圖 Attribute Control Chartspnpcu50控制圖的選用程序控制圖的選用程序注 : 本圖假設(shè)測量系統(tǒng)已經(jīng)過評(píng)價(jià)並且是適用的確定要制定控制圖的特性是計(jì)量型數(shù)據(jù)嗎?樣本容量是否恒定?使用 p 圖關(guān)心的是不合格品率- - 即 壞零件的百份比嗎?使用 n p 或 p 圖關(guān)心的是不合格數(shù)即單位零件不合格數(shù)嗎?樣本容量是否恒定?

31、使用 u 圖使用 c 或u 圖性質(zhì)上是否是均勻或不能按子組取樣- - 例如 : 化學(xué)槽液批量油漆等?子組均值是否能很方便地計(jì)算 ?子組容量是否大於或等於9 ?使用中位數(shù)圖使用x - R 圖是否能方便地計(jì)算每個(gè)子組的S 值 ?使用 x - R 圖使用 x - S 圖否否是是否是否YES否是是是是否否否使用單值圖: X - M R是51控制圖的使用策劃Planning for the Control Charts作控制圖需要按以下步驟：Follow the necessary steps :v計(jì)劃 Planningv資源 Resourcesv評(píng)估和改進(jìn) Evaluation and Improve

32、ment52控制圖的使用策劃Preparation for the use of Control Charts建立適于采取措施的環(huán)境 - 公司文化 Set the right environment to take actions Company Culture確定過程 Define the process確定待管理的特性 (如: 特殊特性) ，考慮Determine characteristics (e.g. Special Characteristics) that need to be managed Shall Consider :v客戶的要求 Customer Requirement

33、sv當(dāng)前及潛在的問題區(qū) Existing and potential problem areav特性間的相互關(guān)系 Interrelation between characteristics確定測量系統(tǒng) Define the Measurement System MSA使不必要的變差最小化 Reduce the variations in those avoidable area53控制圖的使用策劃Preparation for the use of Control Charts過程過程 ProcessProcess輸出輸出 OutputOutput輸入輸入 InputInput使用什么方式？使

34、用什么方式？( (材料材料/ /設(shè)備設(shè)備) )What?What?(Equipment/Raw Material(Equipment/Raw Material)誰進(jìn)行誰進(jìn)行? ? ( (能力能力/ /技能技能/ /培訓(xùn)培訓(xùn)) )Who?Who?(Competence, ability, training)(Competence, ability, training)如何做？如何做？( (方法方法/ /程序程序/ /技術(shù)技術(shù)) )How?How?(Method/Procedure/Technique)(Method/Procedure/Technique)使用的關(guān)鍵準(zhǔn)則是什么？使用的關(guān)鍵準(zhǔn)則是什

35、么？ ( (測量測量/ /評(píng)估評(píng)估) )Key measurement?Key measurement?(Measuring/Evaluation)(Measuring/Evaluation)54Xbar - R Chart 圖Average and Range Chart Average and Range Chart 平均平均數(shù)數(shù) - - 全距控全距控制制圖圖工業(yè)界最常使用的計(jì)量值控制圖The most common chart for the industry55建立Xbar-R控制圖的步驟Set up the steps for X-R Chartsn收集收集數(shù)數(shù)據(jù)據(jù) Collect

36、Data v選擇子組大小，頻率和數(shù)據(jù)Select the subgroup size, frequency and numbers of subgroup 子組大小 Subgroup size : v一個(gè)子組內(nèi)該單元之間出現(xiàn)變差機(jī)會(huì)小(如45件連續(xù)于單一過程的產(chǎn)品) variation among units within the subgroup are small (e.g. 4 to 5 consecutively produced pieces by single production stream) 每個(gè)子組內(nèi)的變差是普通原因造成每個(gè)子組內(nèi)的變差是普通原因造成 Variation w

37、ithin each subgroup reflects COMMON causev代表短時(shí)間內(nèi)零件間變產(chǎn) Represent the piece-to-piece variation within short period of timev不正常變差=過程發(fā)生變化 unusual variation between subgroups = changes in process56建立Xbar-R控制圖的步驟Set up the steps for X-R Chartsv選擇子組大小，頻率和數(shù)據(jù)Select the subgroup size, frequency and numbers of

38、 subgroup 子組頻率 Subgroup frequency :v檢查過程經(jīng)過一段時(shí)間的變化，如: 換班、溫升趨勢、材料變更 To detect the change of process over time, e.g. changes due to work shift difference, warm-up trend, material lots57子組數(shù)大小 Number of Subgroups : v確保變差的主要原因有機(jī)會(huì)出現(xiàn)(25子組包含100個(gè)單值) Major sources of variation have had an opportunity to appear

39、 (25 or more subgroups containing 100 or more readings) v可利用現(xiàn)有數(shù)據(jù)加速研究進(jìn)度Can use existing data to speed up the process建立Xbar-R控制圖的步驟 Set up the steps for X-R Charts58n建立控制圖及記錄原始數(shù)據(jù)Set up control chart and raw data gatheringn 2 3 4 5 A2 1.88 1.02 0.73 0.58 D4 3.27 2.57 2.28 2.11 D3 * * * * 建立Xbar-R控制圖的步驟

40、 Set up the steps for X-R Charts59RAXLCLRAXUCLRDLCLRDUCLKR.RRRKX.XXX2X2X3R4Rk21k21n計(jì)算每個(gè)子組的X平均值和極差R Calculate the Average Range and Process average建立Xbar-R控制圖的步驟 Set up the steps for X-R Charts60UCLCLLCLn子組數(shù)足夠時(shí)(25子組包含100個(gè)單值), 計(jì)算及繪成控制線 試驗(yàn)控制限When number of subgroup is adequate(25 or more subgroups cont

41、aining 100 or more readings), calculate and draw the control limit trial control limits建立建立Xbar-RXbar-R控制控制圖圖的步的步驟驟 Set up the steps for X-R Set up the steps for X-R ChartsCharts61建立Xbar-R控制圖的步驟 Set up the steps for X-R Chartsn過程控制解釋 Explain the Process Controlv分析極差圖(R圖)上的數(shù)據(jù)點(diǎn) Analyse the R chart fir

42、st識(shí)別并標(biāo)注特殊原因(R圖) Identify and mark the special causes糾正及預(yù)防再發(fā)生 Correct and prevent it form recurringv消除受已識(shí)別已識(shí)別的特殊原因影響的子組Exclude all subgroups affected by the identified special cause v重新計(jì)算控制極限(R圖) Recalculate the R control limits62當(dāng)極差受控 過程分佈是穩(wěn)定的,分析平均值圖(Xbar圖)When the ranges are in statistical control,

43、 process spread isstable, thenv看過程的位置是否改變 x 圖 Check if the process location is changing overtime x chartv為繼續(xù)控制延長控制限 Extend the Control Limits for Process Control建立Xbar-R控制圖的步驟 Set up the steps for X-R Charts63控制圖 - 過程的聲音Control Charts- the voice of the processv控制圖可以給我們提供出出現(xiàn)了哪種類型的變差的線索，供我們采取相應(yīng)的措施The

44、control chart can provide us the hints of what types of variations, for the right corrective actions64控制圖上的信號(hào)解釋 Explain The Signals on the Control Chartsv有很多信號(hào)規(guī)則適用于所有的控制圖(Xbar圖和R圖)，主要最常見的規(guī)則 有以下3種：Many types of signals and rules in the XR charts, mainly 3 types:規(guī)則1： 超出控制限的點(diǎn) Rule #1: Points Exceed the

45、 control limitsUCLLCL65控制圖上的信號(hào)解釋Explain The Signals on the Control Charts規(guī)則2： 連續(xù)7點(diǎn)在中心線一側(cè)Rules #2: continuous 7 points in one side of the centre linerunUCLLCL66控制圖上的信號(hào)解釋 Explain The Signals on the Control Charts規(guī)則3： 連續(xù)7點(diǎn)升或下降 Rule #3: continuous 7 points in descending or raisingtrendUCLLCL67過制圖上的信號(hào)解釋

46、Explain The Signals on the Control Charts多于2/3的點(diǎn)落在圖中1/3以外。More than 2/3 of points outside the 1/3 zone 68過制圖上的信號(hào)解釋 Explain The Signals on the Control Charts呈現(xiàn)有規(guī)律變化。 Regular Cyclical Trend69改變控制時(shí)限 Change In Control Limit將這些的控制限畫到控制圖上，并作為不斷進(jìn)行的過程制的基礎(chǔ)。Plot these new control limits on the chart as the ba

47、sis forongoing process control 只要過程的均值和極差保持受控 可將控制限延長以于以后的時(shí)期 As long as the process remains in control for both and range ongoing limits can be extended for additional periods.70圖形圖形 Patterns極差圖極差圖 Range Chart均值圖均值圖 Average Chart超出控制限的點(diǎn) Points beyond the control limits控制限繪錯(cuò) 分佈寬度增加(零件間變化) 測量系統(tǒng)未有足夠分辨或

48、已變化Mis-plotted of control limits Increase or decrease of spread of distribution (piece-to-piece variation) Change in Measurement system or lack of discrimination 控制限繪錯(cuò) 過程已變化 測量系統(tǒng)己變化Mis-plotted of control limits Process has shifted Change in Measurement system 71圖形圖形 Patterns極差圖極差圖 Range Chart均值圖均值圖

49、Average ChartRun 輸出值的分佈寬度增加： 無規(guī)律的成因，如設(shè)備異?；驃A具鬆動(dòng) 測量系統(tǒng)改變 Greater spread of output value due to: irregular cause such as equipment malfunction or loose fixturing shift in process elements such as new , less uniform raw material lots Change in Measurement system 過程均值已變化 測量系統(tǒng)逐漸改變Process average has change

50、d Change in Measurement system such as drift 72 圖形圖形 極差圖極差圖 均值圖均值圖 明顯非隨機(jī)圖形 顯著多於2/3以上的點(diǎn)落在中線外： 控制限繪錯(cuò) 過程或抽樣方法會(huì)被分層：子組系統(tǒng)化包括兩個(gè)或以上的過程流過程均值變化 數(shù)據(jù)被編輯 顯著少於2/3以上的點(diǎn)落在中線外： 過程或抽樣方法形成連續(xù)的分組中包括多個(gè)具不同變化的過程流 顯著多於2/3以上的點(diǎn)落在中線外： 控制限繪錯(cuò) 過程或抽樣方法會(huì)被分層：子組系統(tǒng)化包括兩個(gè)或以上的過程流過程均值變化 數(shù)據(jù)被編輯 顯著少於2/3以上的點(diǎn)落在中線外： 過程或抽樣方法形成連續(xù)的分組中包括多個(gè)具不同變化的過程流 如

51、果存在幾個(gè)過程流，應(yīng)分別識(shí)別和追蹤 73改變控制時(shí)限 Change In Control Limit估計(jì)過程的標(biāo)準(zhǔn)偏差用現(xiàn)在的子組容量計(jì)算：Estimate the process standard deviation. Using the existing subgroup size calculate := = R/dR/d2 2式中 R為子組極差的均值(在極差受控時(shí)期)，d2 隨樣本容量變化的常數(shù)：Where R is the average of the subgroup ranges (for periods with the ranges in control) and d2 is

52、 a constant varying by sample size:n2345678910d21.131.692.062.332.532.702.852.973.0874改變控制時(shí)限 Change In Control Limit按照新的子組容量查表得到系數(shù)d2、D3、D4和A2，計(jì)算新的極差和制限： Using the tabled factors for d2, D3, D4 and A2 based on the new subgroup size, calculate the new range and control limits:= =R Rnewnewd d2 2UCLUCLR

53、 R= = D D4 4 R RnewnewLCLLCLR R= = D D3 3 R RnewnewUCLUCLX X= =X + AX + A2 2 R RnewnewUCLUCLX X= = X - AX - A2 2 R Rnewnew75改變控制時(shí)限 Change In Control Limit將這些的控制限畫到控制圖上，并作為不斷進(jìn)行的過程控制的基礎(chǔ)。Plot the new control limits on the chart as the basis for ongoing process control.只要過程的均值和極差保持受控 可將控制圖的目的是合理、經(jīng)濟(jì)的控制狀態(tài)

54、As long as the process remains in control for both averages and rangesOngoing limits can be extended for additional periods76有關(guān)控制的最后概念用于進(jìn)一步的考慮 n在一個(gè)生產(chǎn)過程中永遠(yuǎn)無法達(dá)到一種完美的控制狀態(tài)。A perfect state of control is never attainable in a production process.n過程控制圖的目的是合理、經(jīng)濟(jì)的控制狀態(tài)。 The goal of the process control charts

55、is reasonable and economical state of control.n如果一張控制圖上從來不出現(xiàn)失控點(diǎn)，我們將嚴(yán)肅地查問該操作是否應(yīng)畫圖。If a chart never went out of control we would seriously question whether that operation should be charted.n對(duì)于車間目的來說，一個(gè)受控的過程即是僅有很少百分比的點(diǎn)失控并且對(duì)失控點(diǎn)采取過適當(dāng)?shù)拇胧?。For shop purposes a controlled process is considered to be one where

56、 only a small percentage of the points go out of control and where out-of-control pointsare followed by proper action. 77請(qǐng)請(qǐng)完成完成 Xbar-RXbar-R控制控制圖圖的制作的制作練習(xí)練習(xí)Please Complete Control Chart Drawing練習(xí) Exercise78控制圖 - 過程的聲音v控制圖可以區(qū)分出普通原因變差和特殊原因變差Control Chart can distinguish the normal causes and the speci

57、al causes特殊原因變差要求立即采取措施Special Causes needs immediate actions減少普通原因變差需要改變產(chǎn)品或過程的設(shè)計(jì)To Reduce the normal causes need product or process redesign79控制圖 - 過程的聲音v錯(cuò)誤的措施 Wrong Actions試圖通過持續(xù)調(diào)整過程參數(shù)來固定住普通原因變差，稱為過度調(diào)整，結(jié)果會(huì)導(dǎo)致更大的過程變差造成客戶滿意度下降Continue to adjust the process parameters to fix the normal process variati

58、ons- over adjustments only cause larger variations and customer unsatisfied試圖通過改變?cè)O(shè)計(jì)來減小特殊原因變差可能解決不了問題，會(huì)造成時(shí)間和金錢的浪費(fèi)Try to change design to reduce the special causes in the variations cannot solve problems, only waste money and time80過度調(diào)整是把每一個(gè)偏離目標(biāo)的值當(dāng)作過程中特殊原因處理的作法 Over adjustment is the practice of treat

59、ing each deviation from the target as if it were the result of the action of a special cause of variation in the process. Results with no adjustment 沒有經(jīng)過調(diào)整的結(jié)果沒有經(jīng)過調(diào)整的結(jié)果Normal Variation 正常變差正常變差 81Note Increasein Variation注意變差增加注意變差增加Result with adjustment to compensate for last deviation from target對(duì)

60、最終目標(biāo)差補(bǔ)償調(diào)整後的結(jié)果Results with adjustment to compensate for last deviation from target if deviation was greater than 1 偏差大於目標(biāo)1個(gè)單位時(shí), 進(jìn)行補(bǔ)償調(diào)整後的結(jié)果Note Increase in Variation注意變差增加注意變差增加82Xbar - S 圖 Chartv平均數(shù) - 標(biāo)準(zhǔn)差控制圖 Average and Std. Dev Control Chart與Xbar - R圖相同 Same as X&R chartsS圖檢出能力較R圖大，但計(jì)算大麻煩S can have