SPC 1

IntroductionIntroduction

• Statistical process controlStatistical process control is a is a collection of tools that when used collection of tools that when used together can result in together can result in process process stabilitystability and and variability reductionvariability reduction

SPC 2

The seven major tools The seven major tools ((品管七大工品管七大工具具 ))(The magnificent seven)(The magnificent seven)

1) Histogram or Stem and Leaf plot1) Histogram or Stem and Leaf plot2) Check Sheet2) Check Sheet3) Pareto Chart3) Pareto Chart4) Cause and Effect Diagram4) Cause and Effect Diagram5) Defect Concentration Diagram5) Defect Concentration Diagram6) Scatter Diagram 6) Scatter Diagram 7) Control Chart7) Control Chart

SPC 3

問題問題• 小華這次小考只有小華這次小考只有 5050 分分——趕快到補習班趕快到補習班報名？報名？

• 顧客抱怨這次的送貨時間延遲顧客抱怨這次的送貨時間延遲——重新設重新設計物流系統？計物流系統？

SPC 4

Chance and Assignable Causes of Chance and Assignable Causes of Quality VariationQuality Variation

• A process that is operating with only A process that is operating with only chance chance causes of variationcauses of variation present is said to be present is said to be in in statistical control.statistical control.

• A process that is operating in the presence of A process that is operating in the presence of assignable causesassignable causes is said to be is said to be out of control.out of control.

• The eventual The eventual goal of SPCgoal of SPC is is reductionreduction or or elimination of variabilityelimination of variability in the process by in the process by identification of assignable causes.identification of assignable causes.

SPC 5

管制圖的目的管制圖的目的• 發現製程有無引起變異的發現製程有無引起變異的非機遇原因非機遇原因，，進而針對原因予以消除，進而針對原因予以消除，維持製程的穩維持製程的穩定定，，防止異常原因之再次發生防止異常原因之再次發生。。

SPC 6

Basic Principles of the Control Chart of the Control Chart

•A typical control chart has control limits set at values such that if the process is in control, nearly all points will lie between the upper control limit (UCL) and the lower control limit (LCL).

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Out-of-Control SituationsOut-of-Control Situations

• If If at least one pointat least one point plots beyond the plots beyond the control limits, the process is control limits, the process is out of out of controlcontrol..

• If the points behave in a If the points behave in a systematicsystematic or or nonrandom mannernonrandom manner, then the process , then the process could be could be out of controlout of control..

SPC 8

Control charts — ExampleControl charts — Example11

• We have a process that we assume the We have a process that we assume the true process mean is true process mean is = 74 and the = 74 and the process standard deviation is process standard deviation is = 0.01. = 0.01. Samples of size 5 are taken giving a Samples of size 5 are taken giving a standard deviation of the sample average, standard deviation of the sample average, , as , as x

0045.05

01.0

nx

SPC 9

Control charts — ExampleControl charts — Example22

• Control limitsControl limits can be set at can be set at 3 standard 3 standard deviationsdeviations from the mean. from the mean.

• This results in “3-Sigma Control Limits” This results in “3-Sigma Control Limits”

UCL = 74 + 3(0.0045) = 74.0135UCL = 74 + 3(0.0045) = 74.0135

CL= 74CL= 74

LCL = 74 - 3(0.0045) = 73.9865LCL = 74 - 3(0.0045) = 73.9865

SPC 10

Relationship between hypothesis Relationship between hypothesis testing and control chartstesting and control charts

• Choosing the control limits is equivalent Choosing the control limits is equivalent to setting up the to setting up the critical regioncritical region for testing for testing hypothesishypothesis

HH00: : = 74 = 74

HH11: : 74 74

SPC 11

Illustration of Control ChartIllustration of Control Chart

SPC 12

General model of a control chart General model of a control chart ——Shewhart control chartsShewhart control charts

where L = distance of the control limit from the where L = distance of the control limit from the center linecenter line

= mean of the sample statistic, w.= mean of the sample statistic, w. = standard deviation of the statistic, w.= standard deviation of the statistic, w.

W WW

W W

UCL LCenter LineLCL L

W

W

SPC 13

Important uses of the control chartImportant uses of the control chart• Most processes Most processes do not operatedo not operate in a state of statistical in a state of statistical

controlcontrol..

• Consequently, the routine and attentive use of Consequently, the routine and attentive use of control control charts will identify charts will identify assignable causesassignable causes. If these causes . If these causes can be eliminated from the process, can be eliminated from the process, variability will be variability will be reducedreduced and the and the process will be improvedprocess will be improved..

• The The control chartcontrol chart only only detectsdetects assignable causes. assignable causes. Management, operator, and engineeringManagement, operator, and engineering actionaction will will be necessarybe necessary to eliminate the assignable causesto eliminate the assignable causes..

• Out-of-control action plans (OCAPs)Out-of-control action plans (OCAPs) are an are an important aspect of successful control chart usage.important aspect of successful control chart usage.

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SPC 15

使用管制圖追蹤改進過程使用管制圖追蹤改進過程

UCL

LCL

LCLLCL

UCLUCL

製程不集中且不穩定

製程集中且穩定 製程額外的改進

SPC 16

Types the control chart Types the control chart ——依數據的性質分類依數據的性質分類 11

• Variables Control ChartsVariables Control Charts– These charts are applied to data that follow These charts are applied to data that follow

a a continuous distributioncontinuous distribution (measurement (measurement data).data).

• Attributes Control ChartsAttributes Control Charts– These charts are applied to data that follow These charts are applied to data that follow

a a discrete distributiondiscrete distribution..

SPC 17

Types the control chart Types the control chart ——依數據的性質分類依數據的性質分類 22

• 計量值質管制圖計量值質管制圖– 平均數與全距管制圖平均數與全距管制圖– 中位數與全距管制圖中位數與全距管制圖– 平均數與標準差管制圖平均數與標準差管制圖– 個別值平均數與全距管個別值平均數與全距管制圖制圖

– 複式管制圖複式管制圖– 機率管制圖機率管制圖– 趨勢管制圖趨勢管制圖……

• 計數值管制圖計數值管制圖– 不良率管制圖不良率管制圖 (p(p管制管制

圖圖 ))

– 不良數管制圖不良數管制圖 (np(np管管制圖制圖 ))

– 缺點數管制圖缺點數管制圖 (c(c管制管制圖圖 ))

– 平均缺點數管圖平均缺點數管圖 (u(u管管制圖制圖 ))

SPC 18

計量值與計數值管圖之優缺點計量值與計數值管圖之優缺點優點優點 缺點缺點

計計量量值值管管制制圖圖

1.1.用於製程管制，時間上甚靈用於製程管制，時間上甚靈敏，容易敏，容易調查原因調查原因並並預測故障預測故障的發生。的發生。2.2.及時並正確地找出事故發生及時並正確地找出事故發生之真正原因，使品質穩定。之真正原因，使品質穩定。

需經常抽樣並予以測定與計算需經常抽樣並予以測定與計算，，且需點上管制圖且需點上管制圖，，較為麻煩且較為麻煩且費時費時。。

計計數數值值管管制制圖圖

1.1.生產完成後才加以抽樣並將生產完成後才加以抽樣並將其分良品與不良品因實際所需其分良品與不良品因實際所需之資料能以簡單的檢查方法得之資料能以簡單的檢查方法得之之2.2.對對工廠整個品質情況工廠整個品質情況了解非了解非常方便常方便

1.1.調查事故發生之原因比較費調查事故發生之原因比較費時間時間。。2.2.有時已製造相當多之不良品有時已製造相當多之不良品，，而無法及時處理而無法及時處理。。3.3.只靠此種管制圖有時只靠此種管制圖有時無法尋無法尋求事故發生之真正原因求事故發生之真正原因。。

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Type of control chart Type of control chart — — 依管制圖的用途分類依管制圖的用途分類

• 製程分析用管制圖製程分析用管制圖– 為決定方針用為決定方針用– 為工程解析用為工程解析用– 為工程能力研究用為工程能力研究用– 為製程管制之準備用為製程管制之準備用

• 管制用管制圖管制用管制圖– 用以控制製程的品質，用以控制製程的品質，於繪製完成後將管制於繪製完成後將管制界限延長，就每日管界限延長，就每日管制特性的數據計算統制特性的數據計算統計量數，並予以點繪計量數，並予以點繪於圖上，以管制製程，於圖上，以管制製程，如不在管制狀態即採如不在管制狀態即採取下列措施：取下列措施：• 追查異常原因追查異常原因• 迅速消除此種原因迅速消除此種原因• 研究理此種原因使其研究理此種原因使其不再發生不再發生

SPC 20

Type of Process VariabilityType of Process Variability11

• StationaryStationary behavior, behavior, uncorrelateduncorrelated data data

• StationaryStationary behavior, behavior, autocorrelatedautocorrelated datadata

• NonstationaryNonstationary behavior behavior

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Type of VariabilityType of Variability22

• Shewhart control charts are Shewhart control charts are most most effectiveeffective when the when the in-control process in-control process datadata is is stationarystationary and and uncorrelateduncorrelated..

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Popularity of control chartsPopularity of control charts1) Control charts are a proven technique 1) Control charts are a proven technique

for for improving productivityimproving productivity..

2) Control charts are effective in 2) Control charts are effective in defect defect preventionprevention..

3) Control charts 3) Control charts prevent unnecessary prevent unnecessary process adjustmentprocess adjustment..

4) Control charts 4) Control charts provide diagnostic provide diagnostic informationinformation..

5) Control charts 5) Control charts provide information provide information about process capabilityabout process capability..

SPC 23

Choice of Control Limits Choice of Control Limits

““99.73% of the Data”99.73% of the Data”

• If approximately 99.73% of the data lies within If approximately 99.73% of the data lies within 33 of the mean (i.e., 99.73% of the data should of the mean (i.e., 99.73% of the data should lie within the control limits), then 1 - 0.9973 = lie within the control limits), then 1 - 0.9973 = 0.0027 or 0.27% of the data can fall outside 30.0027 or 0.27% of the data can fall outside 3 (or 0.27% of the data lies outside the control (or 0.27% of the data lies outside the control limits). limits).

• 0.00270.0027 is the probability of a is the probability of a Type I errorType I error or a or a false alarmfalse alarm in this situation. in this situation.

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管制界限設定為管制界限設定為 ±3±3σσ 的理由的理由• 在統計推論時，將發生在統計推論時，將發生型型 II 或型或型 IIII 誤差誤差。。而在而在 19301930 年代，所有工業型態之廣大經年代，所有工業型態之廣大經驗指出，驗指出， ±3±3σσ 界限提供此兩種錯誤型態界限提供此兩種錯誤型態所產生的所產生的成本成本之間的之間的經濟平衡經濟平衡。。

SPC 25

規格界限與管制上下限規格界限與管制上下限• 規格界限規格界限

– 乃是顧客要求，而工程設計建立的規範。指乃是顧客要求，而工程設計建立的規範。指示產品必須落在此範圍內才會被接受。示產品必須落在此範圍內才會被接受。

• 管制界限管制界限– 乃是統計上的界限。指示樣本平均或樣本全乃是統計上的界限。指示樣本平均或樣本全距因隨機變化可跨越的範圍界限。距因隨機變化可跨越的範圍界限。

SPC 26

規格界限與管制上下限之比較規格界限與管制上下限之比較• 規格界限與管制界限並規格界限與管制界限並無直接相關無直接相關，既，既使製程落在管制界限內，亦可能不合規使製程落在管制界限內，亦可能不合規範要求。範要求。

• 管制界限管制界限 <<規格界限規格界限– 管制界限優良，製程能滿足標準。管制界限優良，製程能滿足標準。

• 管制界限管制界限 >>規格界限規格界限– 離散大時離散大時，改善製程，減小變異。，改善製程，減小變異。– 偏心時偏心時，改善固定性變異，移動平均值至規，改善固定性變異，移動平均值至規格中心。格中心。

– 無法改善製程時亦可考慮修改標準。無法改善製程時亦可考慮修改標準。

SPC 27

Warning Limits on Control ChartsWarning Limits on Control Charts

• Three-sigmaThree-sigma → action limits, → action limits, two-sigmatwo-sigma → → warning limitswarning limits

• Warning limitsWarning limits (if used) are typically set at (if used) are typically set at 2 2 standard deviationsstandard deviations from the mean. from the mean.

• If If one or more pointsone or more points fall betweenfall between the warning the warning limits and the control limits, or limits and the control limits, or closeclose to the to the warning limits the warning limits the process may not be operating process may not be operating properlyproperly..

• Good thingGood thing: warning limits often : warning limits often increase the increase the sensitivitysensitivity of the control chart. of the control chart.

• Bad thingBad thing: warning limits could result in an : warning limits could result in an increased risk of false alarmsincreased risk of false alarms..

SPC 28

Sample Size and Sampling Frequency Sample Size and Sampling Frequency

• In designing a control chart, both the In designing a control chart, both the sample sizesample size to be selected and the to be selected and the frequency of selectionfrequency of selection must be specified. must be specified.

• Larger samplesLarger samples make it make it easier to detect easier to detect small shifts in the processsmall shifts in the process..

• Current practice tends to favor Current practice tends to favor smaller, smaller, more frequent samplesmore frequent samples..

SPC 29

Average Run Length (Average Run Length ( 平均連串長平均連串長度度 ))

• ARL is the average number of points ARL is the average number of points that must be plotted before a point that must be plotted before a point indicates an out-of-control condition.indicates an out-of-control condition.

• The The average run lengthaverage run length (ARL) is a very (ARL) is a very important way of determining the important way of determining the appropriate appropriate sample sizesample size and and sampling sampling frequencyfrequency..

• Let Let pp = probability that any point = probability that any point exceeds the control limitsexceeds the control limits. Then,. Then,

p

1ARL

SPC 30

IllustrationIllustration

• Consider a problem with control limits Consider a problem with control limits set at set at 3 standard deviations3 standard deviations from the from the mean. The probability that a point plots mean. The probability that a point plots beyond the control limits is again, beyond the control limits is again, 0.0027 (i.e., p = 0.0027). Then the 0.0027 (i.e., p = 0.0027). Then the average run length isaverage run length is

3700027.01

0 ARL

SPC 31

What does the ARL tell us?What does the ARL tell us?

• The average run length gives us the The average run length gives us the length of time (or number of samples) length of time (or number of samples) that should plot in controlthat should plot in control before a point before a point plots outside the control limits.plots outside the control limits.

• For our problem, even if the process For our problem, even if the process remains in controlremains in control, an , an out-of-control out-of-control signal will be generatedsignal will be generated every 370 every 370 samples, on average.samples, on average.

SPC 32

Disadvantage of ARLDisadvantage of ARL

• The The standard deviationstandard deviation of the run length of the run length is is very largevery large..

• The The geometric distributiongeometric distribution is very is very skewedskewed..

SPC 33

Average Time to Signal(Average Time to Signal( 平均失控時平均失控時間間 ))

• Sometimes it is more appropriate to Sometimes it is more appropriate to express the performance of the control express the performance of the control chart in terms of the average time to chart in terms of the average time to signal (ATS). Say that signal (ATS). Say that samples are samples are taken at fixed intervals,taken at fixed intervals, h h hours apart hours apart..

1ATS ARL (h)

Ps. ARL0: the ARL when the process is in control=1/α

ARL1: the out-of-control ARL=1/(1-β)

SPC 34

ExampleExample

• Design 1Design 1– Sample size: n=5Sample size: n=5

– Sampling frequency: Sampling frequency: every half hourevery half hour

• Design 2Design 2– Sample size: n=10Sample size: n=10

– Sampling frequency: Sampling frequency: every hourevery hour

SPC 35

Rational Subgroups Rational Subgroups

• Subgroups or samples should be Subgroups or samples should be selected so that if selected so that if assignable causesassignable causes are are present, the present, the chance for differenceschance for differences between subgroupsbetween subgroups will be will be maximizedmaximized, , while the while the chance for differences due to chance for differences due to these assignable causesthese assignable causes within a within a subgroupsubgroup will be will be minimizedminimized..

SPC 36

Selection of Rational SubgroupsSelection of Rational Subgroups• Select consecutive units of productionSelect consecutive units of production..

(( 瞬時法，瞬時法， instant of time method)instant of time method)– Provides a “snapshot” of the process.Provides a “snapshot” of the process.– Effective at detecting process shifts. Effective at detecting process shifts.

• Select a random sample over the entire Select a random sample over the entire sampling intervalsampling interval.(.(定時法， 定時法， period of period of time method)time method)– Can be effective at detecting if the mean has Can be effective at detecting if the mean has

wandered out-of-control and then back in-wandered out-of-control and then back in-control.control.

SPC 37

SPC 38

Analysis of Patterns on Control ChartsAnalysis of Patterns on Control Charts

Nonrandom patterns can indicate out-of-control Nonrandom patterns can indicate out-of-control conditionsconditions

• Patterns such as Patterns such as cyclescycles, , trendstrends, are often of , are often of considerable diagnostic value (more about this in considerable diagnostic value (more about this in Chapter 5)Chapter 5)

• Look for “Look for “runsruns” - this is a sequence of observations of ” - this is a sequence of observations of the same type (the same type (all above the center line, or all below all above the center line, or all below the center line)the center line)

• Runs of say Runs of say 8 observations or more could indicate an 8 observations or more could indicate an out-of-control situationout-of-control situation..– Run up: a series of observations are increasingRun up: a series of observations are increasing– Run down: a series of observations are decreasingRun down: a series of observations are decreasing

SPC 39

Sensitizing Rules for Shewhart Sensitizing Rules for Shewhart Control ChartsControl Charts11

1)1) One point plots outside the 3-sigma control One point plots outside the 3-sigma control limits.limits.

2)2) Two out of three consecutive points plot Two out of three consecutive points plot beyond the 2-sigma warning limits.beyond the 2-sigma warning limits.

3)3) Four out of five consecutive points plot at a Four out of five consecutive points plot at a distance of 1-sigma or beyond from the center distance of 1-sigma or beyond from the center line.line.

4)4) Eight consecutive points plot on one side of the Eight consecutive points plot on one side of the center line.center line.

5)5) Six points in a row steadily increasing or Six points in a row steadily increasing or decreasing.decreasing.

SPC 40

Sensitizing Rules for Shewhart Sensitizing Rules for Shewhart Control ChartsControl Charts22

6)6) Fifteen points in a row in zone C (both above Fifteen points in a row in zone C (both above and below the center line).and below the center line).

7)7) Fourteen points in a row steadily increasing or Fourteen points in a row steadily increasing or decreasing.decreasing.

8)8) Eight points in a row on both sides of the Eight points in a row on both sides of the center line with none in zone C.center line with none in zone C.

9)9) An unusual or nonrandom pattern in the data. An unusual or nonrandom pattern in the data.10)10) One or more points near a warning or control One or more points near a warning or control

limit.limit.

SPC 41

The Rest of the “Magnificent Seven” The Rest of the “Magnificent Seven”

• The control chart is The control chart is most effectivemost effective when when integrated into a comprehensive SPC integrated into a comprehensive SPC program.program.

• The seven major SPC problem-solving tools The seven major SPC problem-solving tools should be used routinely to should be used routinely to identify identify improvement opportunities.improvement opportunities.

• The seven major SPC problem-solving tools The seven major SPC problem-solving tools should be used to should be used to assist in reducing variability assist in reducing variability and eliminating waste.and eliminating waste.

SPC 42

The magnificent sevenThe magnificent seven

1) Histogram or Stem and Leaf plot1) Histogram or Stem and Leaf plot2) Check Sheet2) Check Sheet3) Pareto Chart3) Pareto Chart4) Cause and Effect Diagram4) Cause and Effect Diagram5) Defect Concentration Diagram5) Defect Concentration Diagram6) Scatter Diagram 6) Scatter Diagram 7) Control Chart7) Control Chart8) 8) StratificationStratification

SPC 43

The Frequency DistributionThe Frequency Distribution and Histogram( and Histogram( 直方圖直方圖 ))11

• 間斷分配間斷分配– 蒐集資料蒐集資料– 排序排序– 編製次數分配表編製次數分配表– 繪直方圖繪直方圖

• 次數直方圖次數直方圖• 相對次數直方圖相對次數直方圖• 累積次數直方圖累積次數直方圖• 相對累積次數直方圖相對累積次數直方圖

SPC 44

The Frequency DistributionThe Frequency Distribution and Histogram( and Histogram( 直方圖直方圖 ))22

• 連續分配連續分配– 蒐集資料蒐集資料– 排序排序– 定全距：定全距： R=XR=Xmaxmax-X-Xminmin

– 定組數定組數 (k)(k)• K=(N)K=(N)1/21/2

• 史特吉斯史特吉斯 (Sturgis)(Sturgis) 法則：法則：K=1+3.322logNK=1+3.322logN

• 經験值經験值

– 定組距定組距 (i)(i)• i=R/Ki=R/K

• 取奇數，可使組中點與取奇數，可使組中點與數據有相同之小數點位數據有相同之小數點位數數

– 定組限與組界定組限與組界– 界定組中點界定組中點– 編製次數分配表編製次數分配表– 繪直方圖繪直方圖

SPC 45

直方圖之分析直方圖之分析 11

• 測知製程能力測知製程能力– 良好之製程平均值接近規格中心，變異小。良好之製程平均值接近規格中心，變異小。

• 測查是否混入測查是否混入兩個以上不同群體兩個以上不同群體——雙峯雙峯型型

• 測知有無測知有無假數據假數據——峭壁型峭壁型• 測知分配型態測知分配型態

– 缺齒型缺齒型——測定值或換算方法有偏差測定值或換算方法有偏差– 離島型離島型——工程有某種異常工程有某種異常

SPC 46

直方圖之分析直方圖之分析 22

• 訂定訂定規格界限規格界限——正負四個標準差正負四個標準差• 與規格界限比較判定製程與規格界限比較判定製程

– 在規格界限內在規格界限內——正常正常– 製程偏移製程偏移——固定性因素固定性因素發生問題發生問題 ((設備、機設備、機

器、原料器、原料…… ))– 製程變異大製程變異大——變動性因素變動性因素發生問題發生問題 (( 人員、人員、方法方法…… ))

SPC 47

Check Sheets(Check Sheets( 查檢表查檢表 ))• Useful for Useful for collecting historical or current collecting historical or current

operating dataoperating data about the process under about the process under investigation.investigation.

• 種類種類– 記錄用查檢表記錄用查檢表– 查檢用查檢表查檢用查檢表

• 功用功用– 作為作為日常管理日常管理– 作為作為特別調查特別調查– 調查結果的調查結果的記錄記錄保存保存

SPC 48

查檢用查檢表查檢用查檢表——範例範例空壓機查檢表 日期：空壓機查檢表 日期：

設備別： 擔當者： 檢查員：設備別： 擔當者： 檢查員：NoNo..

查檢項目查檢項目 判定基準判定基準 檢查方法檢查方法 結果結果 異常說明異常說明

11 油位表油位表 油位在油位在 1/21/2 以上以上 目視目視

22 空氣濾清器空氣濾清器 是否清潔是否清潔 目視目視

33 空氣閥空氣閥 位置是否正確位置是否正確 目視目視

44 壓力表壓力表 維持維持 6~8kg/cm6~8kg/cm22 目視目視

55 皮帶皮帶 是否有裂痕鬆脫是否有裂痕鬆脫 目視目視

66 馬達馬達 運轉是否平順運轉是否平順 耳聽耳聽

：正常 ：正常 ：異常 ：異常 ΔΔ ：其他：其他 (( 如拆修如拆修…… ))

SPC 49

記錄用查檢表記錄用查檢表——範例範例塑膠製品不良狀況查檢表 期間：塑膠製品不良狀況查檢表 期間： 檢查人檢查人：：

日期日期不良不良項目項目

2/12/1 2/22/2 2/32/3 2/42/4 2/52/5 2/62/6 合計合計

擦傷擦傷

氣泡氣泡

尺寸不合尺寸不合

其他其他

合計合計

SPC 50

Pareto Chart(Pareto Chart( 柏拉圖柏拉圖 ))• 18971897 年由義大利經濟學家年由義大利經濟學家 Vilfredo PerotoVilfredo Peroto 所所

創，又稱「創，又稱「 ABCABC 圖圖」。首先應用於「所得曲」。首先應用於「所得曲線」之繪製，其認為線」之繪製，其認為少數人擁有社會上大部少數人擁有社會上大部份的財富份的財富，只要控制少數財主即可控制社會，只要控制少數財主即可控制社會財富，此重點控制方法稱為「柏拉圖原則」、財富，此重點控制方法稱為「柏拉圖原則」、「「重點管理重點管理」或「」或「二、八法則二、八法則」。於生產環」。於生產環境中，可根據所搜集的數據，按不良原因、境中，可根據所搜集的數據，按不良原因、不良狀況或不良發生位置等不同區分標準，不良狀況或不良發生位置等不同區分標準，尋求佔最大比率的原因、狀況或位置尋求佔最大比率的原因、狀況或位置，，先分先分析解決關鍵原因，再逐次解決次因素析解決關鍵原因，再逐次解決次因素。。

SPC 51

柏拉圖範例柏拉圖範例

問題的 80% 可能是原因的 20% 所引起的

問題的 80% 可能是原因的 20% 所引起的

沒貼標籤

印刷不良

貼離中心

鬆弛

其他

不良數

SPC 52

Cause and Effect Diagram(Cause and Effect Diagram( 特性要因圖特性要因圖 ))((Ishikawa diagramIshikawa diagram——KaoruKaoru Ishikawa) Ishikawa)

• Once a defect, error, or problem has Once a defect, error, or problem has been identified and isolated for further been identified and isolated for further study, study, potential causespotential causes of this of this undesirable effect must be analyzed.undesirable effect must be analyzed.

• Cause and effect diagrams are Cause and effect diagrams are sometimes called sometimes called fishbone diagramsfishbone diagrams because of their appearancebecause of their appearance

SPC 53

特性要因圖之分析準則特性要因圖之分析準則• 4M1E4M1E

– ManMan– MachineMachine– MaterialMaterial– MethodMethod– EnvironmentEnvironment

• 七要點七要點– 人人– 設備設備– 材料材料– 夾治具夾治具– 方法方法– 測定測定– 搬運搬運

SPC 54

Construct a Cause-and-Effect DiagramConstruct a Cause-and-Effect Diagram

1.1. Define the problemDefine the problem or effect to be analyzed. or effect to be analyzed.2.2. Form the Form the teamteam to perform the analysis. Often the to perform the analysis. Often the

team will uncover potential causes through team will uncover potential causes through brainstormingbrainstorming..

3.3. Draw the effect box and the center line.Draw the effect box and the center line.4.4. Specify the Specify the major potential causemajor potential cause categories categories and join and join

them as boxes connected to the center linethem as boxes connected to the center line5.5. Identify the possible causes and classify them into the Identify the possible causes and classify them into the

categoriescategories in step 4. Create new categories, if in step 4. Create new categories, if necessary.necessary.

6.6. Rank orderRank order the causes to identify those that seem the causes to identify those that seem most likely to impact the problem.most likely to impact the problem.

7.7. Take corrective action.Take corrective action.

SPC 55

特性要因圖特性要因圖

特性

原料方法

機器人力

環境

原因 原因原因

原因原因

原因

原因

原因原因 原因

原因原因

SPC 56

Defect Concentration Diagram(Defect Concentration Diagram( 缺點集中缺點集中圖圖 ))

• A A defect concentration diagramdefect concentration diagram is a is a picture of the unit, showing all relevant picture of the unit, showing all relevant views.views.

• Various types of defects that can occur Various types of defects that can occur are drawn on the pictureare drawn on the picture

• The diagram is then analyzed to The diagram is then analyzed to determine if the determine if the location of the defectslocation of the defects on the unit provides any useful on the unit provides any useful information about the information about the potential causes potential causes of the defectsof the defects..

SPC 57

Scatter Diagram(Scatter Diagram( 散佈圖散佈圖 ))

• The The scatter diagramscatter diagram is a plot of is a plot of two two variablesvariables that can be used to identify that can be used to identify any any potential relationshippotential relationship between the between the variables.variables.

• The shape of the scatter diagram often The shape of the scatter diagram often indicates what type of relationship may indicates what type of relationship may exist.exist.

SPC 58

Stratification(Stratification( 層別法層別法 ))

• 將原機器或操作人員等，分別收集數據，將原機器或操作人員等，分別收集數據，以找出其間的差異，而針對差異加以改以找出其間的差異，而針對差異加以改善的方法。善的方法。

SPC 59

常用之層別對象常用之層別對象時間別時間別 上午上午 //下午、白天下午、白天 //// 晚上晚上、、作業剛開始作業剛開始 // 作業終了作業終了、、星期星期、、

週週、、上旬上旬 //中旬中旬 //下旨下旨 // 、、月月、、季節別等季節別等作業員別作業員別 作業員個人作業員個人、、年齡年齡、、經驗年數經驗年數、、男女別男女別機械設備別機械設備別 機型機型、、機種機種、、性能性能、、新舊新舊、、工場工場、、生產線別生產線別、、夾治具夾治具

作業方法作作業方法作業條件別業條件別

生產線速度生產線速度、、作業方法作業方法、、作業場所作業場所、、批量批量、、抽樣抽樣、、溫溫度度、、壓力壓力、、速度速度、、轉數轉數、、方式別等方式別等

原料原料 製造商製造商、、供應商供應商、、原產地原產地、、廠牌廠牌、、採購時間採購時間、、接收批接收批號號、、製造批號製造批號、、成份零件成份零件、、儲存時間儲存時間、、儲存場所別等儲存場所別等

量測別量測別 量測儀器量測儀器、、量測者量測者、、量測方法別等量測方法別等檢查別檢查別 檢查員檢查員、、檢查場所檢查場所、、檢查方法別等檢查方法別等

環境氣候別環境氣候別 氣溫氣溫、、溫度溫度、、晴雲晴雲、、雨雨、、風季風季、、乾濕季乾濕季、、照明別等照明別等

其他其他 新產品新產品、、初次製造物初次製造物、、良品良品、、不良品不良品、、包裝包裝、、搬運方搬運方法別等法別等

SPC 60

品質活動推行步驟品質活動推行步驟 (( 改善歷程法改善歷程法 ))

• 明示問題並建立改進的目標明示問題並建立改進的目標• 搜集數據搜集數據• 分析問題分析問題• 產生潛在的對策產生潛在的對策• 選取對策選取對策• 執行對策執行對策• 效果確認效果確認• 標準化標準化• 評價評價

PlanPlan

DoDoCheckCheck

ActionAction

SPC 61

Ways to EliminateWays to EliminateNonvalue-Add ActivitiesNonvalue-Add Activities11

• Rearranging the Rearranging the sequence of workstepssequence of worksteps• Rearranging thee Rearranging thee physical location of the physical location of the

operator in the systemoperator in the system• Changing Changing work methodswork methods• Changing the type of Changing the type of equipmentequipment used in used in

the processthe process• Redesigning Redesigning forms and documentsforms and documents for for

more efficient usemore efficient use

SPC 62

Ways to EliminateWays to EliminateNonvalue-Add ActivitiesNonvalue-Add Activities22

• Improving Improving operator trainingoperator training

• Improving Improving supervisionsupervision

• Identifying more Identifying more clearly the function of clearly the function of the process to all employeesthe process to all employees

• Trying to Trying to eliminate unnecessary stepseliminate unnecessary steps

• Trying to Trying to consolidate process stepsconsolidate process steps

SPC 63

問題討論問題討論

學習品質之改善學習品質之改善