Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Transcription

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3 Learning Objectives Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 3

4 9.1 The Cumulative Sum Control Chart Chapter 9 4

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6 The Cumulative Sum Control Chart Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 6

7 The Tabular Cusum Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 7

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10 Cusum Status Chart (Figure 9.3a) Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 10

11 MINITAB Version of Cusum Status Chart Minitab calculates the lower Cusum this way Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 11

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13 Recommendations for Cusum Design Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 13

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15 The Standardized Cusum Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 15

16 Improving Cusum Performance for Large Shifts: The Combined Shewhart-Cusum Scheme Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 16

17 The Fast Initial Response (FIR) Cusum K = 3, H = 12, headstart = H/2 = 6 Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 17

18 H = 12 implies that the cusum signals at sample 3 Without the headstart, it would not signal until sample 6 Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 18

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20 More on Cusums Cusums are often used to determine if a process has shifted off a specified target because it is easy to calculate the required adjustment One-sided sdedcusums sare eoften useful useu Cusums can also be used to monitor variability Cusums are available for other sample statistics (ranges, standard deviations, counts, proportions) Rational a subgroups and cusums s Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 20

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22 The Cusum V-Mask Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 22

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28 9.2 The Exponentially Weighted Moving Average Control Chart The EWMA is Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 28

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30 Steady-state control limits Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 30

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34 Design of the EWMA Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 34

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37 Robustness of EWMA to Non-normal Process Data Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 37

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40 Extensions of the EWMA Fast initial response feature Monitoring i variability Monitoring count data The EWMA as a predictor of process level Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 40

41 9.3 The Moving Average Control Chart Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 41

42 42 Copight (c) 2009 John Wiley & Sons, Inc.

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45 Learning Objectives Chapter 9 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. 45