Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery....

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Chapter 9 1 Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Transcript of Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery....

Page 1: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 1 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 2: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 2 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 3: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 3 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Learning Objectives

Page 4: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 4 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

8.1 The Cumulative Sum Control Chart

Page 5: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 5 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 6: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

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

The Cumulative Sum Control Chart

Page 7: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 7 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

The Tabular Cusum

Page 8: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 8 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 9: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

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

Page 10: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 10 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Cusum Status Chart (Figure 9.3a)

Page 11: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 11 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

MINITAB Version of Cusum Status Chart

Minitab calculates the lower Cusum this way

Page 12: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 12 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 13: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 13 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Recommendations for Cusum Design

Page 14: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 14 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 15: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 15 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

The Standardized Cusum

Page 16: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 16 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Improving Cusum Performance for Large Shifts: The Combined Shewhart-Cusum Scheme

Page 17: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 17 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

The Fast Initial Response (FIR) Cusum

K = 3, H = 12, headstart = H/2 = 6

Page 18: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 18 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

H = 12 implies that the cusum signals at sample 3 Without the headstart, it would not signal until sample 6

Page 19: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 19 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 20: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 20 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

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 cusums are often useful• Cusums can also be used to monitor variability• Cusums are available for other sample statistics

(ranges, standard deviations, counts, proportions) • Rational subgroups and cusums

Page 21: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 21 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 22: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 22 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

The Cusum V-Mask

Page 23: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 23 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 24: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 24 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 25: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 25 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 26: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 26 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 27: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 27 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 28: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 28 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

9.2 The Exponentially Weighted Moving Average Control Chart

The EWMA is

Page 29: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 29 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 30: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 30 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Steady-state control limits

Page 31: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 31 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 32: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 32 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 33: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 33 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 34: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 34 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Design of the EWMA

Page 35: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 35 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 36: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 36 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 37: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 37 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Robustness of EWMA toNon-normal Process Data

Page 38: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 38 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 39: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 39 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 40: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 40 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Extensions of the EWMA

• Fast initial response feature

• Monitoring variability

• Monitoring count data

• The EWMA as a predictor of process level

Page 41: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 41 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

9.3 The Moving Average Control Chart

Page 42: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 42 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 43: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 43 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 44: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 44 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Page 45: Chapter 91Introduction to Statistical Quality Control, 6 th Edition by Douglas C. Montgomery. Copyright (c) 2009 John Wiley & Sons, Inc.

Chapter 9 45 Introduction to Statistical Quality Control, 6th Edition by Douglas C. Montgomery.Copyright (c) 2009  John Wiley & Sons, Inc.

Learning Objectives