SPC统计过程控制介绍培训课件PPT

1、1统计过程控制介绍Introduction To Statistical Process Control2统计过程控制介绍Introduction To Statistical Process Control3数理统计的应用过程结果测量数据收集分析反馈4收集哪些数据合格品的数量市场占有率产品参数-直径，性能，过程参数-温度，压力，时间，5必然事件在一定条件下结果必然会出现。例如：水的沸腾 冰的溶化还有：6不可能事件在一定条件下结果不能出现例如：平原中50度的水沸腾 常温中冻冰还有：7随机事件在一定条件下，结果可能出现、也可能不出现例如：工人在一定条件下生产合格/不合格产品；还有：赢/输球 成功

2、/失败8概率和频率项目特点实例概率理论值；精确但获得难；掷钱币的正反面的可能性频率试验值；实用易得到；产品的合格率高考的及格率9Attribute vs. Variable Data计数数值和计量数值 Attribute data is generally charted as Go/No Go entries. The part is either good or not good. 计数数值通常是通过或不通过，好或不好 Gages can be used to check attribute dimensions. An example is a plug gage that would

3、be used to check a bore.量具是用来检查尺寸的特性。例如：塞棒用来检测孔 Variable data is quantifiable (measurable to a specific dimension that can be recorded).计量数值是可测量的（测量具体的尺寸）10产品特性的确定产品标准；产品参数；顾客的要求；过程要求；过程参数；11抽样方法抽签法查随机数表（用在DOE中）系统抽样法（生产中常用）采用每间隔一定的时间/空间进行抽样的方法GB2828-199912NORMAL DISTRUBUTION/正态分布THE BELL SHAPED CURV

4、E/钟型曲线2 =68%4 = 95%1 2 -3 3 6 = 99.73%-2 -1 X13STANDARD DEVIATION 标准偏差CpkUSL-X or X-LSLPPM%0.67230853769.14631.0036680793.31931.334621099.3791.67523399.97672.0063.499.99966过程能力和PPM、合格率的关系14ERROR DETECTION MODEL检测模式MachinesMaterialsWorkforceMethodsEnvironmentProductProcessMassInspectionScrap orRework

5、OKBadCustomer过程调整Adjust Process15ERROR PREVENTION MODEL预防模式MachinesMaterialsWorkforceMethodsEnvironmentProductProcessInspectionOKSPCCustomerMonitorAdjust16变差Variation过程的单个输出之间的差异。17Common Cause Variation普通原因变差The many sources of variation that occur in a process that is in statistical control.很多变差的发

6、生在统计控制过程机器的清洗和轴承的磨损备件更换计划 、润滑系统的更新环境温度、湿度等18Special Cause Variation特殊原因Unpredictable variation that occasionally and infrequently occurs in a process.不可预知的变差只是偶尔或很少发生Tool wear/工具磨损/失效Broken tool/工具损坏Drop in air pressure/气压降低Coolant lines clogged/管路冷凝Wrong material supplied to production line/生产线得到错误

7、的材料19Process Capability= Cp 过程能力Cp is a number which relates to how much tolerance you are using.Cp是一个描述公差的指数Cp should be equal to or greater than 1.5 to control a Cpk of 1.33Cp应大于或等于1.5,为了是 Cpk达到1.33.20Process Capability= Cp Represents the process variation as compared to the total tolerance.过程变差和总

8、变差的比值Is the ratio of the total tolerance to 6 sigma.The formula is Cp = Total Tolerance 6 sigma21控制图实践Control Chart Practice22计量型数据控制图Variable Control chart类 型优 点应 用 均值极差图XR较简单，对子组内特殊原因较敏感广泛均值标准差图XSS较R更准确有效，尤其大样本容量。计算机实时记录，样本容量大。中位数图XR用中间值代替均值，不用计算。车间工人易操作。单值移动极差图XRM用单值代替均值，相邻数值差代替极差。用于测量难度较大的产品。23计

9、数型数据控制图Attribute Control Chart 类 型应用范围不合格品率P图广泛不合格品数NP图不合格品数比不合格品率更有意义各个时期子组的容量不变不合格数C图 连续的产品流上，（如布匹）单个检验中发现不同原因造成的不合格（车辆维修）单元不合格数U图适用于与C图相同的数据，但不同时期的样本容量不同时，必须采用U图。24控制图/CONTROL CHARTSRXTHE MOST COMMONLY USED CONTROLCHART IS CALLED THE X-BAR, R CHART.通常我们把控制图称为“XR”图 25控制图绘制过程确定过程确定样本参数（数值、特性、样本数量）周

10、期收集过程的样本数据（每日、每班、每小时）计算样本的平均值计算样本的R值（差值）在图中标注X&R值计算控制的上限和下限26控制图数据收集按控制计划收集样本的数据和频率27控制图RXX = X1 + X2 + X3 + .XnSAMPLE SIZE (n)X = 3 + 5 + 4 + 4 4=R = XHIGH - XLOWR = 5 - 3 =24计算X - R的值28控制图计算X - R的值RXX =X1 + X2 + X3 + .XnNO. OF SAMPLESR1 + R2 + R3 + .RnNO. OF SAMPLESR =29控制图RXX=RGrand AverageAverag

11、e Range平均值30控制图上、下控制限UPPER AND LOWER CONTROL LIMITSSAMPLE A2 D3 D4 SIZE 2 1.88 0 3.27 3 1.02 0 2.57 4 .73 0 2.28 5 .58 0 2.11For Sample Sizes of Less ThanSeven, the LCL for the RangeChart is Always “0”.RXX-BAR CHARTUCLX = X + (A2 x R)=LCLX = X - (A2 x R)=RANGE CHARTUCLR = D4 x RLCLR = D3 x R31CONTRO

12、L CHARTSRXX=RGrand AverageAverage RangeUCLLCLUCLLCL上、下控制限32Control Limits and Specification Limits控制限和公差极限 Control limits are established by natural process variation. 控制限是根据普通过程变差建立 Specification limits are established by the tolerance assigned to a dimension. 公差极限是公差允许的极限尺寸 To produce good product

13、 the control limits must be within the specification limits. 制造好的产品，控制极限必须控制在规格极限内33超出控制条件Out of Control Conditions当你违反休哈特八项规则中任何一项过程中存在特殊原因34超出控制条件Out of Control Conditions如果超出过程的控制限你必须：记录结果实施控制计划中的反应计划35Accurate Data Entry正确输入数据必须对样本的尺寸连续输入必须按控制计划中规定的尺寸和频率。即使超出部份也要画在图上，为了得到过程能力的测量评估。注意：单值移动极差图是用在一

14、个样件。36CONTROL CHARTS/控制图UPPER CONTROL LIMITLOWER CONTROL LIMIT中心线CENTERLINEZONE AZONE BZONE CZONE CZONE BZONE A3o3o2o2oo o37CONTROL CHARTS/控制图判定准侧过程处于稳定状态：连续25个点都在控制界限内；连续35个点，至多1个点在控制界限外；连续100个点，至多2个点在控制界限外。过程异常判断准侧休哈特准侧（Shewhart rule）38SHEWHART RULES休哈特控制规则之一：至少有一个标定点位于控制极限外ABABCC39SHEWHART RULES休

15、哈特规则AABBCC之二：连续的三个点有二个在同一A区或以上40SHEWHART RULESAABBCC之三：五个点中有四个在同一面B区或更远处41SHEWHART RULESAABBCC之四: 八个点在同一侧的C区或远处42SHEWHART RULESAABBCCAABBCC之五：: C区有15个连续的标定点 分辨率不够43SHEWHART RULESAABBCC之六: 8个连续的点在两面的C区之外ABC之间刻度太小44SHEWHART RULESAABBCC之七：有14个连续的上下交错的标定点45SHEWHART RULESAABBCC之八: 有连续6个标定点上升/下降46Process

16、Capability Coefficient =Cpk Cpk is a number value assigned by comparing the process aim to the blueprint nominal.Cpk是过程目标和设计目标的比值Cpk must be equal to or greater than 1.33 for current product, or 1.67 on new products. A Cpk of 1.00 is assumed when the dimension is checked 100% at the operation where

17、it is created.批量每个产品的Cpk大于/等于1.33，新产品大于/等于1.67。 Cpk =1.0尺寸应100%检验。Cpk is always less than or equal to the Cp for bilateral (+/-) tolerances.双向公差时。 Cpk总是小于或等于Cp。47PROCESS CAPABILITY INDEXCpk Cpl =X - LSL3 SigmaORCpu =USL - X3 Sigma REPRESENTS THE PROCESS VARIATION AND ALSO INCLUDES AIM, AS COMPARED T

18、O THE TOTAL TOLERANCE. 表示过程变差和总变差的比较 TELLS THE CAPABILITY OF THE PROCESS BASED ON THE WORST CASE VIEW OF THE DATA. 以最低的数据表明过程能力 THE FORMULA IS THE LESSER OF: 公式中的小值48课程练习Class Exercise看后面一个工件的练习；收集数据并计算Cp和Cpk。4950Class ExerciseBPN = .760+/- 0.25 Cpu = _ = USL XX = .? 3 sigmaR = .?Cpl =_ = X - LSL US

19、L = _ 3 sigmaLSL = _Cpk = _ONE SIGMA = _R/d2_3 SIGMA = _6 SIGMA = _Cp = _ = total tolerance 6 sigma51Class ExerciseBPN = .760Cpu = 1 .056 = USL XX = .728 3 sigmaR = .185Cpl = 0.816 = X - LSL USL = 1.01 (.760 + .25) 3 sigmaLSL = 0.51 (.760 - .25)Cpk = .816 ONE SIGMA = .0803 SIGMA = .2396 SIGMA = .477

20、Cp = 1.048 = total tolerance 6 sigma52Class ExerciseX=.728BPN (.76)1o.8082o.8883o.968USL1.01-1o.648-2o.568-3o.488LSL.511 sigma equals .08053Class Exercise让我们使过程变得更好！我们和上级讨论，他已经做了设备的维护并安排高质量的材料。两个星期后我们发现我们已经降低了过程的变差，西格玛从0.080降到0.07054Class Exercise在过程公差不变的情况下，计算新的 Cp. Cp = .50 /.42 = 1.2 我们的过程能力从 .93

21、6 to 1.2GOOD JOB! 55Class ExerciseUSL1.01LSL.51=X.728BPN (.76)1 sigma equals .0703o.9382o.8681o.798-1o.639-2o.550-3o.51856课程练习计算在过程目标不变的情况下的 Cpk .Cpl =X - LSL3 Sigma= (.728 - .51)_ .21 (3 X .070)=1.04Cpu =USL - X3 Sigma= (1.01 - .728)_ .21 =1.3457Class Exercise我们调整了控制尺寸，一周后，发现我们的过程目标从 .728 提高到 .740平

22、均值更接近中值（BPN）计算 Cpk.Cpl =X - LSL3 Sigma= (.740 - .51)_ .21 =1.1Cpu =USL - X3 Sigma=(1.01 - .740)_ .21 =1.34 GOOD JOB!58Class ExerciseUSL1.01LSL.51BPN (.76)X=.7403o.9502o.8801o.810-1o.670-2o.600-3o.5301 sigma equals .07059Estimated Process Capability评估过程能力一个或多个零件外形尺寸的特征值的研究Piece part dimension study o

23、n one or more features.还应用于机械和工具能力的研究Also used for machine and tooling capability studies.工件必须在没有调整机器和工具的情况下生产Parts must be run without making adjustments to machine and tooling.Cpk 必须大于/等于 1.33 对定型产品， 大于/等于 1.67 对新产品.Cpk must be equal to, or greater than, 1.33 for current products, or 1.67 for new

24、products.60评估过程能力Estimated Process Capability图纸规格Blueprint Specification = 450 +/- 130测量数据Data Values d2=2.32655042344844629637244847357549939742347362642339734647349949939752642357544834632139755047344837242352652449939752434642347360044844827044849952442355061评估过程能力Estimated Process CapabilityX =

25、_1 sigma = _3 sigma = _X + 3 sigma = _X 3 sigma = _Cpu = USL X = _ = _ 3 sigmaCpl = X LSL = _ = _ 3 sigmaCpk = _62评估过程能力Estimated Process CapabilityX = 454.11 sigma = 87.53 sigma = 262.5X + 3 sigma = 716.6 (454.1 + 262.5)X 3 sigma = 191.6 (454.1 262.5)Cpu = USL X = 580 454.1 = .48 3 sigma 262.5Cpl =

26、 X LSL = 454.1 - 320 = .51 3 sigma 262.5Cpk = .4863标准偏差和极差STANDARD DEVIATION AND RANGER_R_R_X=X=X=不同的标准偏差和极差值64过程能力满足规范PROCESS CAPABLE OF MEETING THE SPECIFICATIONLOWERSPEC.LIMITUPPERSPEC.LIMITLCLUCLLSLUSLLCLUCLX=X=所有的输出都在规范内，只是变差的水平不同65过程能力不满足规范PROCESS NOT CAPABLE OF MEETING THE SPECIFICATION输出超过一个或两个控制限LSLUSLLCLUCLLSLUSLLCLUCLX=X=66过程能力指标PROCESS CAPABILITY INDEX Cpk =