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Copyright (c) 2005 John Wiley & Sons, Inc.

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Presentation on theme: "Copyright (c) 2005 John Wiley & Sons, Inc."— Presentation transcript:

1

2 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

3 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

4 Copyright (c) 2005 John Wiley & Sons, Inc.
Process Capability Natural tolerance limits are defined as follows: Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

5 Copyright (c) 2005 John Wiley & Sons, Inc.
Uses of process capability data: Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

6 Reasons for Poor Process Capability
Process may have good potential capability Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

7 Copyright (c) 2005 John Wiley & Sons, Inc.
Data collection steps: Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

8 Example 7-1, Glass Container Data
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

9 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

10 Probability Plotting Mean and standard deviation could be estimated from the plot Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

11 Copyright (c) 2005 John Wiley & Sons, Inc.
The distribution may not be normal; other types of probability plots can be useful in determining the appropriate distribution. See Chapter 2, also Figure 7-6. Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

12 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

13 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

14 Copyright (c) 2005 John Wiley & Sons, Inc.
Practical interpretation – relationship of PCR to the proportion of the tolerance interval used by the process: For the hard bake process: Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

15 Copyright (c) 2005 John Wiley & Sons, Inc.
One-Sided PCR Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

16 Interpretation of the PCR
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

17 Assumptions for Interpretation of Numbers in Table 7-2
Violation of these assumptions can lead to big trouble in using the data in Table 7-2. Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

18 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

19 Copyright (c) 2005 John Wiley & Sons, Inc.
Cp does not take process centering into account It is a measure of potential capability, not actual capability Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

20 A Measure of Actual Capability
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

21 Normality and Process Capability Ratios
The assumption of normality is critical to the usual interpretation of these ratios (such as Table 7-2) For non-normal data, options are Transform non-normal data to normal Extend the usual definitions of PCRs to handle non-normal data Modify the definitions of PCRs for general families of distributions Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

22 Other Types of Process Capability Ratios (Section 7-3.5)
First generation Second generation Third generation Lots of research has been done to develop ratios that overcome some of the problems with the basic ones Not much evidence that these ratios are used to any significant extent in practice Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

23 Copyright (c) 2005 John Wiley & Sons, Inc.
Confidence intervals are an important way to express the information in a PCR Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

24 CI is wide because the sample size is small
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

25 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

26 CI is wide because the sample size is small
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

27 Copyright (c) 2005 John Wiley & Sons, Inc.
Recommended for use when the process is not in control. Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

28 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

29 Copyright (c) 2005 John Wiley & Sons, Inc.
Specifications not needed to estimate parameters and establish stability Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

30 Copyright (c) 2005 John Wiley & Sons, Inc.
Since LSL = 200 Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

31 Copyright (c) 2005 John Wiley & Sons, Inc.
Use DOX to isolate sources of variability Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

32 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

33 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

34 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

35 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

36 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

37 Estimating the Variance Components
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

38 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

39 The gauge is not capable by this criterion
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

40 Copyright (c) 2005 John Wiley & Sons, Inc.
Discrimination Ratio Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

41 We have focused only on precision
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

42 Copyright (c) 2005 John Wiley & Sons, Inc.
Gauge R&R Studies Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

43 Copyright (c) 2005 John Wiley & Sons, Inc.
Gauge R&R studies are usually conducted with a factorial experiment Variance Components Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

44 Copyright (c) 2005 John Wiley & Sons, Inc.
This is a two-factor factorial experiment ANOVA methods are used to conduct the R&R analysis Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

45 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

46 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

47 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

48 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

49 Copyright (c) 2005 John Wiley & Sons, Inc.
Negative estimates of a variance component would lead to filling a reduced model, such as, for example: Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

50 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

51 Copyright (c) 2005 John Wiley & Sons, Inc.
For this Example Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

52 Other Topics in Gauge R&R Studies
Section provides a description of methods to obtain confidence intervals on the variance components and measures of gauge R&R Section presents a new measure of gauge capability, the probabilities of misclassification of parts Rejecting good units (producer’s risk) Passing bad units (consumer’s risk) Methods for calculating these two probabilities are given Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

53 Copyright (c) 2005 John Wiley & Sons, Inc.
Linear Combinations Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

54 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

55 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

56 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

57 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

58 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

59 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

60 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

61 Copyright (c) 2005 John Wiley & Sons, Inc.
For the normal distribution with unknown mean and variance: Difference between tolerance limits and confidence limits Nonparametric tolerance limits can also be calculated Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

62 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

63 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.

64 Copyright (c) 2005 John Wiley & Sons, Inc.
Chapter 7 Introduction to Statistical Quality Control, 5th Edition by Douglas C. Montgomery. Copyright (c) 2005  John Wiley & Sons, Inc.


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