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1、品質管理與管制,1,Tools for Design Optimization,Taguchi loss functionOptimizing reliability,1,品質管理與管制,2,Key Idea,Design optimization includes setting proper tolerances to ensure maximum product performance and making designs robust,that is,insensitive to variations in manufacturing or the use environment.,2
2、,品質管理與管制,3,田口損失函數（Taguchi loss function）,田口假設損失可用一種平方函數來估算，使得偏離目標值越遠相當於損失越大。損失函數表示為：,品質管理與管制,4,Loss Functions,4,Traditional View,Taguchis View,品質管理與管制,5,Taguchi Loss Function Calculations,Loss function:L(x)=k(x-T)2,Example:Specification=.500.020.Failure outside of the tolerance range costs$50 to rep
3、air.Thus,50=k(.020)2.Solving for k yields k=125,000.The loss function is:L(x)=125,000(x-.500)2Expected loss=k(2+D2)where D is the deviation from the target.,5,品質管理與管制,6,品質管理與管制,7,傳統的品質一致性之經濟模型,總成本,不一致成本,品質保證成本,品質“最佳水準”,100%,品質管理與管制,8,現代的品質一致性之經濟模型,總成本,不一致成本,品質保證成本,100%,品質管理與管制,9,Optimizing Reliabili
4、ty,StandardizationRedundancyPhysics of failure,9,品質管理與管制,10,Tools for Design Verification,Reliability testingMeasurement systems evaluationProcess capability evaluation,品質管理與管制,11,Key Idea,Design verification is necessary to ensure that designs will meet customer requirements and can be produced to
5、specifications.,品質管理與管制,12,Reliability testing,Life testingAccelerated life testingEnvironmental testingVibration and shock testingBurn-in(component stress testing),品質管理與管制,13,Measurement System Evaluation,Whenever variation is observed in measurements,some portion is due to measurement system error
6、.Some errors are systematic(called bias);others are random.The size of the errors relative to the measurement value can significantly affect the quality of the data and resulting decisions.,品質管理與管制,14,度量衡（Metrology）量度之科學,準確度（Accuracy）：定義為觀測值接近已接受參考值或標準的一致性。精密度（Precision）：定義為隨機選取個別量度或結果之間的一致程度。,品質管理與
7、管制,15,品質管理與管制,16,重複性和可再測性研究,1.選出m個操作員和n個零件，一般來說至少選2個操作員和10個零件。要讓操作員看不到零件編號。2.校準測量儀器。3.讓每個操作員以隨機的次序測量各零件，並記錄結果。針對總共r次試驗重複此程序；但必須要試驗兩次以上。4.計算每個操作員的平均測量值，以及最大和最小平均值的差異。5.計算各零件和各操作員的全距：這些值，顯示同一個操作員重複測量同一個零件的變異性。接下來，計算各操作員的平均全距：計算整體平均全距。6.計算個別全距 的管制界限。,品質管理與管制,17,Repeatability and Reproducibility,Repeata
8、bility(equipment variation)variation in multiple measurements by an individual using the same instrument.Reproducibility(operator variation)-variation in the same measuring instrument used by different individuals,品質管理與管制,18,Repeatability&Reproducibility Studies,Quantify and evaluate the capability
9、of a measurement systemSelect m operators and n partsCalibrate the measuring instrumentRandomly measure each part by each operator for r trialsCompute key statistics to quantify repeatability and reproducibility,品質管理與管制,19,Spreadsheet Template,品質管理與管制,20,R&R Evaluation,Under 10%error-OK10-30%error-m
10、ay be OKover 30%error-unacceptable,品質管理與管制,21,Key Idea,One of the most important functions of metrology is calibrationthe comparison of a measurement device or system having a known relation-ship to national standards against another device or system whose relationship to national standards is unkno
11、wn.,品質管理與管制,22,Process Capability,品質管理與管制,23,Process Capability,The range over which the natural variation of a process occurs as determined by the system of common causesMeasured by the proportion of output that can be produced within design specifications,品質管理與管制,24,Process Capability for Variable
12、s,品質管理與管制,25,Process Capability for Variables,品質管理與管制,26,Process Capability for Variables,品質管理與管制,27,Types of Capability Studies(1),Peak performance studyHow a process performs under ideal conditionsProcess characterization studyHow a process performs under actual operating conditions,品質管理與管制,28,Typ
13、es of Capability Studies(2),Component variability studyRelative contribution of different sources of variation(e.g.,process factors,measurement system),品質管理與管制,29,Process Capability Study,Choose a representative machine or processDefine the process conditionsSelect a representative operatorProvide t
14、he right materialsSpecify the gauging or measurement methodRecord the measurementsConstruct a histogram and compute descriptive statistics:mean and standard deviationCompare results with specified tolerances,品質管理與管制,30,Process Capability,品質管理與管制,31,Process Capability Index,Cp=,USL-LSL 6s,Cpl,Cpu,USL
15、-m 3s,Cpl=,m-LSL 3s,Cpk=min,Cpu=,品質管理與管制,32,Process Capability Ratios,Non-centered process(general case):choose cpk=the lower of:Upper Spec Limit Process Mean cpu=-or 3 Process Mean Lower Spec Limit cpl=-3,品質管理與管制,33,Process Capability Example-1,SpecificationNominal(target)dimension:30 mmTolerance:+
16、1 mm,-0.5 mm Process standard deviation:0.25 31 30 30 29.5cpu=-=1.33 cpl=-=0.67 3(0.25)3(0.25)and therefore Cpk=0.67,品質管理與管制,34,Process Capability Ratios,Centered process(special case):specification width cp=-process width Upper Spec Limit Lower Spec Limit=-6,品質管理與管制,35,Process Capability Example-2,
17、SpecificationNominal(target)dimension:30 mmTolerance:1 mm Process standard deviation:0.25 31 29 cp=-=1.33 6(0.25),品質管理與管制,36,Process Capability Requirements,Process must be normally distributedProcess must be in controlProcess capability result:1.33=capable and acceptable(generally)2.00=capable and
18、acceptable(6)5 or 10 is“overkill”,excessive resource use,SJSU Bus.142 David A.Bentley 0/24/06,品質管理與管制,37,Process Capability Spreadsheet Template,品質管理與管制,38,Capability Versus Control,Process capability(Cp or Cpk)Measure of variability against design specificationsSpecs set by customer or design engin
19、eerSpec width:USL&LSL(or UTL<L)Statistical process control(SPC)Measure of variability against control limitsControl limits calculated from sample dataUCL and LCL,品質管理與管制,39,Capability Versus Control,THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,40,Process C
20、ontrol vs.Capability,品質管理與管制,41,Process Capability,The range over which the natural variation of a process occurs as determined by the system of common causesMeasured by the proportion of output that can be produced within design specifications,41,品質管理與管制,42,Types of Capability Studies,Peak performa
21、nce study-how a process performs under ideal conditionsProcess characterization study-how a process performs under actual operating conditionsComponent variability study-relative contribution of different sources of variation(e.g.,process factors,measurement system),42,品質管理與管制,43,Process Capability
22、Study,Choose a representative machine or processDefine the process conditionsSelect a representative operatorProvide the right materialsSpecify the gauging or measurement methodRecord the measurementsConstruct a histogram and compute descriptive statistics:mean and standard deviationCompare results
23、with specified tolerances,43,品質管理與管制,44,製程能力研究的六個步驟,1.選擇一個具代表性的機器或製程。2.定義製程條件。3.選出一個具代表性的操作員。4.提供充足而標準等級的物料，使研究不致中斷。5.訂出所用的測量方法。6.提出依序紀錄產出單位的測量值與條件的方法。,品質管理與管制,45,品質管理與管制,46,品質管理與管制,47,Process Capability,47,品質管理與管制,48,Key Idea,The process capability index,Cp(sometimes called the process potential in
24、dex),is defined as the ratio of the specification width to the natural tolerance of the process.Cp relates the natural variation of the process with the design specifications in a single,quantitative measure.,48,品質管理與管制,49,Process Capability Index,49,Cp=,UTL-LTL 6s,Cpl,Cpu,UTL-m 3s,Cpl=,m-LTL 3s,Cpk
25、=min,Cpu=,品質管理與管制,50,Spreadsheet Template,品質管理與管制,51,製程能力指標,品質管理與管制,52,單邊製程能力指標,品質管理與管制,53,本章結束,THANKS!,品質管理與管制,54,第 12 章,六標準差設計,品質管理與管制,55,六標準差設計（Design for Six Sigma;DFSS）,DFSS包含四種主要活動：1.概念的發展，此時基於客戶要求、技術能力，和經濟現實狀況，而決定產品的功能性。2.設計的發展，專注於產品和服務的性能，必須要滿足產品和服務的製造或交貨要求。3.設計最佳化，設法使生產或使用的變異性最小，即開發一種強健設計。4
26、.設計的確認，確保系統產能符合適當的標準差水準。,品質管理與管制,56,Key Idea,DFSS的多數工具就像六標準差般已行之有年;但其獨特之處，是把他們融合成正式的理論方法,由六標準差哲學主導,並切記明確的企業目標。,56,品質管理與管制,57,概念發展的工具,概念設計Concept development 是應用科學、工程、以及企業知識，來產生基本的功能設計，同時滿足顧客、和製造或服務的要求。品質機能展開(QFD)概念工程,57,品質管理與管制,58,Key Idea,研發基本功能設計，是把顧客需求轉換成可衡量的技術量度，以及轉換成後續的細部設計規格。,58,品質管理與管制,59,品質機
27、能展開,品質機能展開（quality function deployment;QFD）使在整個設計過程以及設計生產系統時，能滿足顧客的需求。這個名詞，是從描述流程的字Kanji翻譯而來。常用一種矩陣圖來呈現數據和資訊。,品質管理與管制,60,品質機能展開,60,品質管理與管制,61,Key Idea,透過改善價值鏈中所有機制的溝通和團隊合作，如行銷與設計之間設計與製造之間以及採購與供應商之間，故QFD使公司蒙受其利。,61,品質管理與管制,62,品質屋,62,品質管理與管制,63,品質屋（The House of Quality）,建造品質屋有六個基本步驟：1.確認顧客需求。2.確認技術需求。
28、3.把顧客需求和技術需求產生關聯。4.評估競爭性的產品或服務。5.評估技術需求，並擬定目標值。6.決定在其餘生產/交貨流程中，要佈署什麼技術需求。,品質管理與管制,64,品質管理與管制,65,品質管理與管制,66,品質管理與管制,67,品質管理與管制,68,品質管理與管制,69,品質管理與管制,70,概念工程（Concept Engineering;CE）,主要步驟：1.瞭解顧客的環境。2.把瞭解轉換成需求。3.把已得知者轉化為作業。5.概念的遴選。4.概念的產生。,品質管理與管制,71,可靠度設計 Design for Reliability,品質管理與管制,72,發展設計的工具,公差設計設
29、計失效模式和影響分析可靠度預測,72,品質管理與管制,73,公差設計,決定某個尺寸允許的變異。工程師須瞭解成本與性能的權衡取捨。,73,品質管理與管制,74,公差設計(1),規格 Specification將顧客需求轉換為設計需求。包含名義尺寸(nominal dimensions)和公差(tolerances).名義值 Nominal value製造時設法滿足顧客需求的理想尺寸或目標值公差 Tolerance名義值上下所允許的變異體認到製程中有自然的變異(稱為一般原因common causes),品質管理與管制,75,Tolerance Design(2),考慮成本與性能的權衡取捨太緊的公差
30、=不必要的成本太鬆的公差=不符合顧客需求最終的結果:太鬆或太緊都會耗費你的錢!,品質管理與管制,76,Key Idea,由於五個 M：men and women,materials,machines,methods,and measurement，製程中有自然的變異(稱為一般原因common causes)，所以不是所有的零件都能剛好依照名義規格來生產，因此公差是必要的。,76,品質管理與管制,77,設計失敗模式和影響分析DFMEA,設計失效模式和影響分析（design failure mode and effects analysis;DFMEA）的目的，是要找出所有可能會發生失敗的途徑，估
31、計失敗的結果與嚴重性，以及建議矯正設計的措施。,品質管理與管制,78,78,品質管理與管制,79,可靠度模型Reliability Models,品質管理與管制,80,可靠度,可靠度 Reliability 定義某個產品、某件設備，或系統，針對一段指定時間，在指定的運轉條件下，能執行預期功能的機率。此定義有四個要素：機率、時間、功能(績效)，和運轉條件。,80,品質管理與管制,81,功能(績效)失效的種類,功能性失效(Functional failure)由於製造或材料的缺陷，產品壽命一開始就發生失效。“新品故障，DOA，Dead on Arrival”“早期失敗，夭折，infant mort
32、ality”可靠度失效(Reliability failure)使用一段時間後的失效。,81,品質管理與管制,82,可靠度測量,失效率 Failure rate(l)每單位時間失效的次數替代的測量平均失效時間(MTTF，Mean time to failure)平均失效間隔時間(MTBF，Mean time between failures),THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,83,可靠度的種類Types of Reliability,固有的可靠性Inhe
33、rent reliability 依據產品設計所預測（穩健設計）實現可靠性Achieved reliability 在使用過程中觀察,THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM(Mod 11/11/02 DAB),品質管理與管制,84,累積失效百分比曲線Cumulative Failure Rate Curve,THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制
34、,85,可靠度模型Reliability Models,品質管理與管制,86,Key Idea,很多電子組件普遍在壽命早期，展現高卻遞減的失效率(如曲線陡峭的斜率所證明),接著是失效綠鄉邦穩定時期，而以失效率遞增結束。,86,品質管理與管制,87,平均失效率曲線Average Failure Rate,THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,88,失敗率(failure rate）,品質管理與管制,89,品質管理與管制,90,可靠度的函數,失效的機率密度函數 f
35、(t)=le-lt for t 0時間間隔(0,T)內失效之機率 F(t)=1 e-lT 可靠度函數(不會在T時間內失效的機率 R(T)=1 F(T)=e-lT,品質管理與管制,91,系統可靠度,品質管理與管制,92,串聯系統可靠度,品質管理與管制,93,串聯系統,RS=R1 R2.Rn,THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,94,串聯可靠度之例,元件可靠度:.95,.96,.94,.90系統可靠度:(.95)(.96)(.94)(.90)=0.77,品質管理
36、與管制,95,並聯可靠度,品質管理與管制,96,並聯系統,RS=1-(1-R1)(1-R2).(1-Rn),THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,97,並聯可靠度之例,元件可靠度:.95,.96,.94,.90系統可靠度:1-(1-.95)(1-.96)(1-.94)(1-.90)=0.999988,品質管理與管制,98,串-並聯系統,轉換成等價的串聯系統,A,B,C,C,D,RA,RB,RC,RD,RC,A,B,C,D,RA,RB,RD,RC=1(1-RC)(1-RC),THE MANAGEMENT AND CONTROL OF QUALITY,5e,2002 South-Western/Thomson LearningTM,品質管理與管制,99,串-並聯系統之例,元件可靠度:.95(s),.96(p),.94(p),.90(s)並聯部份的可靠度:1-(1-.96)(1-.94)=0.9976系統可靠度:(.95)(.9976)(.90)=0.8529,
