Page 9 - Six Sigma for electronics design and manufacturing

Contents
viii
2.1.5
42
The Cpk Approach Versus Six Sigma
2.2
2.2.1
Cpk and process average shift
43
2.2.2
44
Negative Cpk
45
2.2.3
Choosing six sigma or Cpk
Setting the process capability index
46
2.2.4
2.3
Calculating Defects Using Normal Distribution
47
Relationship between z and Cpk
54
2.3.1
54
2.3.2 Six sigma and the 1.5 shift 41
Example defect calculations and Cpk
2.3.3 Attribute processes and reject analysis for 57
six sigma
2.4 Are Manufacturing Processes and Supply Parts 59
Always Normally Distributed?
2.4.1 Quick visual check for normality 59
2.4.2 Checking for normality using chi-square tests 60
2.4.3 Example of goodness of fit to normal 62
2
distribution test
2.4.4 Transformation data into normal distributions 63
2.4.5 The use of statistical software for 65
normality analysis
2.5 Conclusions 65
2.6 References and Bibliography 66
Chapter 3. Six Sigma and the Manufacturing Control Systems 69
3.1 Manufacturing Variability Measurement and Control 70
3.2 The Control of Variable Processes and Its 72
Relationship with Six Sigma
3.2.1. Variable control chart limits 74
3.2.2 Control chart limits calculations 74
3.2.3 Control and specifications limits 75
3.2.4 X , R variable control chart calculations 76
example
3.2.5 Alternate methods for calculating control 78
limits
3.2.6 Control chart guidelines, out-of-control 78
conditions, and corrective action
procedures and examples
3.2.7 Examples of variable control chart 82
calculations and their relationship to
six sigma
3.3 Attribute charts and their Relationship with 84
Six Sigma