SPCbilingual.ppt

1、统计过程控制工作坊 SPC Work Shop,-企业管理的好帮手,基本统计概念 Basic SPC Concept,统计学 (Statistics) 收集、 整理、展示 、分析 、解析统计资料 Collect, collate, display, analysis, explain of data 由样本推论母体/群体 From sample to project the population 能在不确定情况下作决策 Decision with uncertainty 是一门科学方法、决策工具 Scientific and decision tool,基本统计概念 Basic SPC Con

2、cept,抽样,推论,统计量 Statistical Value R 全距 (range) 算术平均数 (arithmetic mean) Md 中位数 (median) Mo众数 (mode) 2 方差/变异 (variance) 标准差 (standard deviation),基本统计概念Basic SPC Concept,R 全距 (range) R = Xmax - Xmin 算术平均数 (arithmetic mean),基本统计概念Basic SPC Concept,Md 中位数 (median) 顺序数列中的中心项的数值 The medial number in the ser

3、ies Mo众数 (mode) 资料中出现最多的数值 The number with highest frequency,基本统计概念Basic SPC Concept,2 方差/变异 (variance),基本统计概念Basic SPC Concept,标准差 (standard deviation),基本统计概念Basic SPC Concept,例：Case 1, 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,基本统计概念Basic SPC Concept,数据的收

4、集与整理Data Collection and Collation,Action,Test,Analysis,数据Data,结 Conclusion,样本Sample,群体Population,Sampling,抽 样,数据收集 Data Collection,数据整理 Data Collate - 次数分配 Frequency Distribution,直方图 (Histogram),分布曲线 Distribution Curve,正态(常态)分布的曲线图Normal Distribution Curve,正态分布的性质Nature of Normal Distribution,数据 Dat

5、a 直方图Histogram 分布曲线 Distribution,直方图 Histogram 分布 Distribution,正常型Normal,直方图 Histogram 分布 Distribution,偏向型 Bias,直方图Histogram 分布Distribution,孤岛型 Island,过程变差Process Variation,输入 (材料)Input (Material),人 Man,方法 Method,过程 (生产/装配)Process,输出(产品)Output (Product),反馈(测量/检验)Feedback (Test/Insp.),测量系统MSA),材料Mate

6、rial,过程变差 Process Variation,机器 Machine,过程变差 Process Variation,输入材料 Material Input 不同批次之间的差异 Lot to Lot Variation 批次内的差异 Within Lot Variation 随时间产生的差异 Variation in Time Series 随环境而产生的差异 Variation due to Environment,过程变差 Process Variation,生产/装配 Production/ Assembly 设备及工装夹具的差异 Equipment and Tooling Var

7、iation 随时间而产生的磨损，漂移等 Aging and Shift by time 操作工之间的差异(如手工操作的过程) Variation between Operators ( Manual Work) 设置的差异 Different Setup 环境的差异Different Environments,过程变差 Process Variation,输出产品 Output Product 输出的产品随时间而产生的变化 Product Variation by time series 输出的产品随环境而产生的变化 Product Variation due to environment,

8、过程变差 Process Variation,反馈 - 测量 Feedback- Measurement 由于测量用于过程中的所有组成部分，测量的变差会对过程的各个阶段产生影响 Measurements are part of the process, variation in the measurement can affect the process in various stages 偏倚 Bias 稳定性 Stability 重复性 Repeatability 再现性 Reproducibility 分辨率 Resolution,持續改進過程循環的各個階段,2. 維護過程 監控過程性能

9、 查找偏差的特殊原因並採取措施,3. 改進過程. 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 本過程應做些什麼? 會出現什麼錯誤? 本過程正在做什麼? 達到統計控制狀態? 確定能力,計劃,實施,措施,研究,計劃,措施,實施,研究,計劃,實施,措施,研究,过程变差 Process Variation,每件产品的尺寸与别的不同 Each product dimension has differences SPEC,过程变差 Process Variation,但它们形成一个模型，若稳定，可以描述为一个分布 The data are grouped to form the mod

10、el. If stable, it can be descried as the distribution.,过程变差 Process Variation,分布可以通用过以下因素来加以区分 Distribution can be descried with various elements,或这些因数的组合 Or the combination of these elements,位置 Position,分布宽度置 Spread,形状 Form/ Shape,过程变差 Process Variation,如果只存在变差的普通原因， 随著时间的推移，过程的输出 形成一个稳定的分布并可预测,If

11、there are only the common causes, and move in time series, the process outputs are predictable with stable distribution,目标直线 Target Line,过程变差 Process Variation,目标直线 Target Line,预测 Forecast,范围 Spec,时间 Time,如果存在变差的特殊原因，随著时间的推移，过程的输出不稳定 If the special cause is in the variation, in time series, the proc

12、ess become unstable,？,？,？,？,？,？,？,？,？,？,？,？,？,？,？,过程控制和过程能力Process Control and Process Capability,过程控制 Control Process,受控 In Control (消除了特殊原因) Eliminate the Special Cause,不受制 Out Of Control (存在特殊原因) with Special Cause,过程变差 Process Variation,Distribution can be described by: Location (typical value)位

13、置 (典型值) Spread 分布宽度 Shape(pattern of variation)形状 (变差的模式),Typical value典型值,Spread分布,过程变差 Process Variation,过程的变差分两个类型 Two Categories 特殊原因造成的变差 Special Causes 普通原因造成的变差 Common Causes,过程变差 Process Variation,普通原因变差 Common Causes in Variation 影响过程中每个单位 affect each unit in the process 是由所有不可分派的小变差源组成 For

14、med by various variation sources; and 但遵循一个分布 follow a particular distribution 通常需要采取系统措施来减小 Use system corrective actions to reduce 在控制图上表现为随机性random point in the control chart If only common cause, the process output of a process is Predictable如只有普遍原因，输出是可预计的过程。,过程变差 Process Variation,特殊原因变差 Speci

15、al Causes in Variation 间断的，偶然的，通常是不可预测的和不稳定的变差 Discontinued, accidental, unpredictable and unstable 非随机的图案 Non random pattern 是由可分派的变差源造成该变差源可以被纠正 Can be corrected, the cause is from the particular source,过程变差 Process Variation,工业经验建议为：Industrial Experience 局部措施 Local action 通常用来消除变差的特殊原因Usually req

16、uired to eliminate special causes of variation 通常由与过程直接相关的人员实施 Usually taken by people close to the process 大约可纠正15%的过程问题 Only 15% of process problem can be corrected,过程变差 Process Variation,工业经验建议为：Industrial Experience 对系统采取措施 Actions on the system 通常用来消除变差的普通原因 Usually required to eliminate / or r

17、educe common causes of variation, and be taken by management 大约可纠正85%的过程问题 About 85% of process problem can be corrected,过程控制和过程能力Process Control and Process Capability,过程能力 Process Capability,受控且有能力符合规范 (普通原因造成特变差) Control and capable to fit the spec (variation due to Normal Cause),受控但没有能力符合规范 Cont

18、rol but without capability to fit the spec (普通原因造成变差太大) Large variation due to Normal Cause,Spec,时间 Time,过程控制和过程能力Process Control and Process Capability,每个过程可以分类如下：Each process can be categorized as: Control or out of control ? 受控或不受控? Fit the customer requirements ? 是否有满足客户要求 ?,过程控制和过程能力,第1类 (符合要求，

19、受控) Case 1 (Accept, In Control) 是理想状况。为持续改进可能需要进一步减小变差Ideal Status, to reduce variation for continuous improvement. 第2类 (不符合要求，受控) Case 2 (Not Accept, In Control) 存在过大的普通原因变差 with large variation from normal cause 短期内，进行100%检测以保护客户不受影响 In short term, go for 100% inspection to reduce the effect for c

20、ustomer 必须进行持续改善以减少普通原因的变差 Must go for continuous improvement to eliminate the effect from common cause,过程控制和过程能力Process Control and Process Capability,第3类 (符合要求，不受控) Case 3. Accept but OUT of control 有相对较小的普通原因及特殊原因变差With less normal and special causes 如果存在的特殊原因已经明确但消除具影响可能不大经济，客户可能接受这种过程状况 If the

21、special causes are known but the cost may be high to eliminate them, customer may accept this process status.,过程控制和过程能力,第4类 (不符合要求，不受控) Case 4 ( Not Accept, OUT of Control) 存在过大的普通原因及特殊原因的变差 Larger Normal and special causes in the variation 需要进行100%检测以保护客户利益 必须采取紧急措施使过程稳定，并减小变差 Must go for contingen

22、cy/ containment actions to stable the process and reduce variations, 100% inspection to protect customer,过程控制和过程能力,判断一个过程是否满足规格要求： Judge the process can fit the spec requirements Capability Index 能力指数 - Cpk (For stable Process only 只用於穩定过程) Performance Index 性能指数 Ppk 判断一个 过程是受控还是不受控用：Judge the proce

23、ss is in control or out of control 控制图 Control Charts,控制图 Control Charts 为判断制程变差的普通原因或特殊原因的主要统计分析工具To judge the process variation with COMMON or SPECIAL cause as the major statistical analysis tool,基本概念 Basic Concept,控制图中包括三条线 3 lines in Control Chart 控制上限 (Upper Control Limit; UCL) 中心线 (Center Line

24、; CL) 控制下限 (Lower Control Limit; LCL),UCL CL LCL,控制图的种类 Type of Control Charts,计量型数据的控制图 Variable Control Charts Xbar-R Xbar-S X-MR 计数型数据的控制图 Attribute Control Charts p np c u,控制圖的選用程序,注 : 本圖假設測量系統已經過評價並且是適用的,控制图的使用策划Planning for the Control Charts,作控制图需要按以下步骤：Follow the necessary steps : 计划 Plannin

25、g 资源 Resources 评估和改进 Evaluation and Improvement,控制图的使用策划Preparation for the use of Control Charts,建立适于采取措施的环境 - 公司文化 Set the right environment to take actions Company Culture 确定过程 Define the process 确定待管理的特性 (如: 特殊特性) ，考虑Determine characteristics (e.g. Special Characteristics) that need to be manage

26、d Shall Consider : 客户的要求 Customer Requirements 当前及潜在的问题区 Existing and potential problem area 特性间的相互关系 Interrelation between characteristics 确定测量系统 Define the Measurement System MSA 使不必要的变差最小化 Reduce the variations in those avoidable area,控制图的使用策划Preparation for the use of Control Charts,过程 Process,输

27、出 Output,输入 Input,使用什么方式？(材料/设备) What?(Equipment/Raw Material),谁进行? (能力/技能/培训)Who?(Competence, ability, training),如何做？(方法/程序/技术) How?(Method/Procedure/Technique),使用的关键准则是什么？ (测量/评估) Key measurement?(Measuring/Evaluation),Xbar - R Chart 图,Average and Range Chart 平均数 - 全距控制图 工业界最常使用的计量值控制图 The most co

28、mmon chart for the industry,建立Xbar-R控制图的步骤Set up the steps for X-R Charts,收集数据 Collect Data 选择子组大小，频率和数据Select the subgroup size, frequency and numbers of subgroup 子组大小 Subgroup size : 一个子组内该单元之间出现变差机会小(如45件连续于单一过程的产品) variation among units within the subgroup are small (e.g. 4 to 5 consecutively pr

29、oduced pieces by single production stream) 每个子组内的变差是普通原因造成 Variation within each subgroup reflects COMMON cause 代表短时间内零件间变产 Represent the piece-to-piece variation within short period of time 不正常变差=过程发生变化 unusual variation between subgroups = changes in process,建立Xbar-R控制图的步骤Set up the steps for X-R

30、Charts,选择子组大小，频率和数据Select the subgroup size, frequency and numbers of subgroup 子组频率 Subgroup frequency : 检查过程经过一段时间的变化，如: 换班、温升趋势、材料变更 To detect the change of process over time, e.g. changes due to work shift difference, warm-up trend, material lots,子组数大小 Number of Subgroups : 确保变差的主要原因有机会出现(25子组包含1

31、00个单值) Major sources of variation have had an opportunity to appear (25 or more subgroups containing 100 or more readings) 可利用现有数据加速研究进度Can use existing data to speed up the process,建立Xbar-R控制图的步骤 Set up the steps for X-R Charts,建立控制图及記錄原始數據Set up control chart and raw data gathering,建立Xbar-R控制图的步骤

32、Set up the steps for X-R Charts,计算每个子组的X平均值和极差R Calculate the Average Range and Process average,建立Xbar-R控制图的步骤 Set up the steps for X-R Charts,UCL CL LCL,子组数足夠時(25子组包含100个单值), 計算及繪成控制線 試驗控制限When number of subgroup is adequate(25 or more subgroups containing 100 or more readings), calculate and draw

33、the control limit trial control limits,建立Xbar-R控制图的步骤 Set up the steps for X-R Charts,建立Xbar-R控制图的步骤 Set up the steps for X-R Charts,过程控制解释 Explain the Process Control 分析极差图(R图)上的数据点 Analyse the R chart first 识别并标注特殊原因(R图) Identify and mark the special causes 糾正及預防再發生 Correct and prevent it form rec

34、urring 消除受已識別的特殊原因影響的子組Exclude all subgroups affected by the identified special cause 重新计算控制极限(R图) Recalculate the R control limits,當极差受控 過程分佈是穩定的,分析平均值图(Xbar图) When the ranges are in statistical control, process spread is stable, then 看过程的位置是否改变 x 图 Check if the process location is changing overtim

35、e x chart 为继续控制延长控制限 Extend the Control Limits for Process Control,建立Xbar-R控制图的步骤 Set up the steps for X-R Charts,控制图 - 过程的声音Control Charts- the voice of the process,控制图可以给我们提供出出现了哪种类型的变差的线索，供我们采取相应的措施 The control chart can provide us the hints of what types of variations, for the right corrective a

36、ctions,控制图上的信号解释 Explain The Signals on the Control Charts,有很多信号规则适用于所有的控制图(Xbar图和R图)， 主要最常见的规则 有以下3种： Many types of signals and rules in the XR charts, mainly 3 types: 规则1： 超出控制限的点 Rule #1: Points Exceed the control limits,控制图上的信号解释Explain The Signals on the Control Charts,规则2： 连续7点在中心线一侧 Rules #2:

37、 continuous 7 points in one side of the centre line,控制图上的信号解释 Explain The Signals on the Control Charts,规则3： 连续7点升或下降 Rule #3: continuous 7 points in descending or raising,过制图上的信号解释 Explain The Signals on the Control Charts,多于2/3的点落在图中1/3以外。 More than 2/3 of points outside the 1/3 zone,过制图上的信号解释 Exp

38、lain The Signals on the Control Charts,呈现有规律变化。 Regular Cyclical Trend,改变控制时限 Change In Control Limit,将这些的控制限画到控制图上，并作为不断进行的过程 制的基础。 Plot these new control limits on the chart as the basis for ongoing process control 只要过程的均值和极差保持受控 可将控制限延长以于以后的时期 As long as the process remains in control for both an

39、d range ongoing limits can be extended for additional periods.,改变控制时限 Change In Control Limit,估计过程的标准偏差用现在的子组容量计算： Estimate the process standard deviation. Using the existing subgroup size calculate :,=,R/d2,式中 R为子组极差的均值(在极差受控时期)，d2 随样本容量变化的常数： Where R is the average of the subgroup ranges (for peri

40、ods with the ranges in control) and d2 is a constant varying by sample size:,改变控制时限 Change In Control Limit,按照新的子组容量查表得到系数d2、D3、D4和A2，计算新的极差和制限： Using the tabled factors for d2, D3, D4 and A2 based on the new subgroup size, calculate the new range and control limits:,=,Rnew,d2,UCLR,=,D4 Rnew,LCLR,=,

41、D3 Rnew,UCLX,=,X + A2 Rnew,UCLX,=,X - A2 Rnew,改变控制时限 Change In Control Limit,将这些的控制限画到控制图上，并作为不断进行的过程控制的基础。 Plot the new control limits on the chart as the basis for ongoing process control.,只要过程的均值和极差保持受控 可将控制图的目的是合理、经济的控制状态 As long as the process remains in control for both averages and ranges Ong

42、oing limits can be extended for additional periods,有关控制的最后概念用于进一步的考虑,在一个生产过程中永远无法达到一种完美的控制状态。A perfect state of control is never attainable in a production process. 过程控制图的目的是合理、经济的控制状态。 The goal of the process control charts is reasonable and economical state of control. 如果一张控制图上从来不出现失控点，我们将严肃地查问该操作

43、是否应画图。If a chart never went out of control we would seriously question whether that operation should be charted. 对于车间目的来说，一个受控的过程即是仅有很少百分比的点失控并且对失控点采取过适当的措施。For shop purposes a controlled process is considered to be one where only a small percentage of the points go out of control and where out-of-c

44、ontrol pointsare followed by proper action.,请完成 Xbar-R控制图的制作练习 Please Complete Control Chart Drawing,练习 Exercise,控制图 - 过程的声音,控制图可以区分出普通原因变差和特殊原因变差 Control Chart can distinguish the normal causes and the special causes 特殊原因变差要求立即采取措施 Special Causes needs immediate actions 减少普通原因变差需要改变产品或过程的设计 To Redu

45、ce the normal causes need product or process redesign,控制图 - 过程的声音,错误的措施 Wrong Actions 试图通过持续调整过程参数来固定住普通原因变差，称为过度调整，结果会导致更大的过程变差造成客户满意度下降 Continue to adjust the process parameters to fix the normal process variations- over adjustments only cause larger variations and customer unsatisfied 试图通过改变设计来减小

46、特殊原因变差可能解决不了问题，会造成时间和金钱的浪费 Try to change design to reduce the special causes in the variations cannot solve problems, only waste money and time,过度调整是把每一个偏离目标的值当作过程中特殊原因处理的作法 Over adjustment is the practice of treating each deviation from the target as if it were the result of the action of a special

47、 cause of variation in the process.,Results with no adjustment 沒有經過調整的結果,Normal Variation 正常變差,Note Increasein Variation注意變差增加,Result with adjustment to compensate for last deviation from target對最終目標差補償調整後的結果,Results with adjustment to compensate for last deviation from target if deviation was great

48、er than 1 偏差大於目標1個單位時, 進行補償調整後的結果,Note Increase in Variation注意變差增加,Xbar - S 图 Chart,平均数 - 标准差控制图 Average and Std. Dev Control Chart 与Xbar - R图相同 Same as X&R charts S图检出能力较R图大，但计算大麻烦 S can have better detection than R, trouble in calculation 一般样本大小n小于是9使用R图，n大于9使用S图 Sample size N9, use S charts 配合电脑使

49、用 Use with PC,Xbar - S 图 Chart,X - MR 图Chart,个别值 - 移动全距控制图 Moving Range Control Charts 数据不能合理分组时使用 Data not suitable for the sub grouping 在下列情况可使用：In the following situation: 一次只能收集到一个数据，生产效率及损耗率。 Can collect a single data per time, by considering the efficiency and scrap 制程品质极为均匀，不需多取样本，如液体浓度。 The

50、product itself is very evenly distributed, no more sampling, like Conc. 取得测定值既费时成本又高，如复杂的化学分析及破坏性试验。 Costly for the measurement, such as complicated chemical analysis, and destructive test.,X - MR 图,计数型数据控制图Attribute Control Charts,P图 (P Charts) nP图(nP Charts) C图 (C Charts) U图 (U charts),P 图 (P Char

51、ts),不合格品率(不良率)控制图 Failure Rate Control Chart 分析或控制制程不合格品率(不良率) Analyse or control the failure rate 样本大小n可以不同 Sample size n can varies,P 图 (P Charts),P 图 (P Charts),nP 图 (nP Charts),不合格品数(不良数)控制图Non conforming no ( No of defective) Control Chart 分析或控制制程不合格品数(不良数)Analyse and Control of Non conforming

52、no ( No of defective) Control Chart 样本大小n要相同Sample Size N must be the same,nP 图 (nP Charts),C 图 C Charts,缺点数控制图Defect Point Control Chart 分析或控制制程缺点数 Analyse or Control of Defect Point Control Chart 样本大小 n 要相同 Sample Size N must be the same,C 图 -在样本大小一致的子组内的不合格数,u 图 U Charts,单位缺点数控制图 Unit defective C

53、ontrol Charts 分析或控制制程单位缺点数Analyse or Control of Unit defective Control Charts 样本大小 n 可以不同Sample Size n can varies,u 图 U charts,过程能力Process Capability,过程控制和过程能力Process Control & Process Capability,判断一个 过程是受控还是不受控用： To judge the process are in control or out of control: 控制图 Control Chart 判断一个过程是否满足规格要

54、求： To judge the process can fulfill the specification : 能力指数 Cpk ( Process Capability) 性能指数 - Ppk ( Performance Capability),短期 Short Term 长期 Long Term,过程能力 Process Capability,Short Term,Long Term,过程能力的研究 Process Capability Study,短期,特殊原因,短期能力研究 - 过程性能 Short Term- Performance Capability,6,过程能力的研究 Process Capability Study,过程性能 (Process Performance) 过程总变差 特殊原因变差 + 普通原因变差 Total Process Variation due to both Special and Common Cause 由 估计出 Estimate form Sigma,s,过程能力的研究 Process Capability Study,输入 (材料),过程 (生产/装配),输出 (产品),反馈 (测量/检验),长期能力研究 - 过程能力 Long Term Capability Study