Introduction to Statistical Quality Control, 4th Edition

1. Introduction to Statistical Quality Control, 4th Edition Introduction to Statistical Quality Control, 4th Edition Douglas C. Montgomery Arizona State University

2. Introduction to Statistical Quality Control, 4th Edition Chapter 1 Quality Improvement in the Modern Business Environment

3. Introduction to Statistical Quality Control, 4th Edition 1-1. The Meaning of Quality and Quality Improvement 1-1.1 Dimensions of Quality 1-1.2 Quality Engineering Technology

4. Introduction to Statistical Quality Control, 4th Edition 1-1.1 Dimensions of Quality Performance Reliability Durability Serviceability Aesthetics Features Perceived Quality Conformance to standards

5. Introduction to Statistical Quality Control, 4th Edition Performance Will the product perform its intended function? Will this industrial scale measure up to 4000 pounds in 5 pound graduations?

6. Introduction to Statistical Quality Control, 4th Edition Reliability How often does the product fail? How often do I have to take this Toyota Camry to the service department?

7. Introduction to Statistical Quality Control, 4th Edition Durability How long will the product last? The product should perform satisfactorily over a long period of life If I buy that 1999 Toyota 4Runner when the lease expires, will it give me good service for 10 more years?

8. Introduction to Statistical Quality Control, 4th Edition Serviceability How easy is it to repair the product? If amazon.com sends the wrong book, how hard is it to get this error corrected?

9. Introduction to Statistical Quality Control, 4th Edition Aesthetics Is the product pleasing to the senses? Do you like the box in which Timberland Shoes are packaged?

10. Introduction to Statistical Quality Control, 4th Edition Features What will the product do beyond the basics? Does the new Ford Focus come with a CD changer, or do you have to pay extra for that?

11. Introduction to Statistical Quality Control, 4th Edition Perceived quality What is the reputation of the company selling this product? Is Delta really ready when you are? Why do people buy Gucci handbags?

12. Introduction to Statistical Quality Control, 4th Edition Conformance to standards Is the product made as designed? Why do they have to beat on those Ford Taurus bodies when they are being assembled in Hapeville?

13. Introduction to Statistical Quality Control, 4th Edition 1-1.1 Dimensions of Quality Definitions of Quality Quality means fitness for use - quality of design - quality of conformance Quality is inversely proportional to variability.

14. Introduction to Statistical Quality Control, 4th Edition Quality of design Automobile differences Materials used in construction Specifications of the components Reliability of drive train components Reliability of accessories

15. Introduction to Statistical Quality Control, 4th Edition Quality of conformance How well does the product conform to the specifications required by the design? Choice of manufacturing processes Training of the workers Supervision of the workers Motivation of the workers Quality-assurance procedures that were used

16. Introduction to Statistical Quality Control, 4th Edition Quality is inversely proportional to variability Toyota Lexus versus Ford Taurus That transmission noise (or lack of it) is wasted energy caused by components that don�t fit precisely Imprecise components lead to wear and tear Ford Taurus/Mercury Sable transmission lasts for 64,000 miles

17. Introduction to Statistical Quality Control, 4th Edition 1-1.1 Dimensions of Quality �  Transmission Example

18. Introduction to Statistical Quality Control, 4th Edition 1-1.1 Dimensions of Quality Quality Improvement Quality improvement is the reduction of variability in processes and products. Alternatively, quality improvement is also seen as �waste reduction.�

19. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Quality Characteristics Physical - length, weight, voltage, viscosity Sensory - taste, appearance, color Time Orientation - reliability, durability, serviceability

20. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Quality engineering is the set of operational, managerial, and engineering activities that a company uses to ensure that the quality characteristics of a product are at the nominal or required levels.

21. Introduction to Statistical Quality Control, 4th Edition Inherent variability No two products are ever identical Slight differences in materials Slight differences in machine settings Slight differences in operators Slight differences in ambient temperature during production Papermate Pens not much different Fins on a turbine engine quite a lot

22. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Two types of data: Attributes Data - discrete data, often in the form of counts Variables Data - continuous measurements such as length, weight Both types will be discussed in the course

23. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Specifications Quality characteristics being measured are often compared to standards or specifications. Desired measure for the quality characteristic Example: Shaft and bearing Too loose the assembly will wobble causing wear Too tight, and the assembly can not be made, no clearance

24. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Specifications Nominal or target value Desired value for a quality characteristic

25. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Specifications Upper Specification Limit (USL) Lower Specification Limit (LSL) Largest and smallest allowable values

26. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Specifications Upper Specification Limit (USL) Lower Specification Limit (LSL) One-sided The compression strength of a Coke bottle must be greater than a given psi value Two-sided The weight of potato chips in the bag can be between 7.8 and 8.3 ounces

27. Introduction to Statistical Quality Control, 4th Edition Design specifications Over the wall From design to manufacturing Cooperatively Between design and manufacturing

28. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology When a component or product does not meet specifications, it is considered to be nonconforming. A nonconforming product is considered defective if it has one or more nonconformities that may seriously affect the safe or effective use of the product.

29. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology A new car is purchased A bubble in the paint on the door is noticed Nonconformity � yes Defective car - no

30. Introduction to Statistical Quality Control, 4th Edition 1-1.2 Quality Engineering Terminology Concurrent Engineering Team approach to design. Specialists from manufacturing, quality engineering, management, etc. work together for product or process improvement.

31. Introduction to Statistical Quality Control, 4th Edition 1-2. A Brief History of Quality  Control and Improvement (Refer to Table 1-1) Frederick Taylor (1875) introduces the principles of scientific management; dividing work into tasks with standardized procedures The Gilbreths developed standard times and motions (1920s)

32. Introduction to Statistical Quality Control, 4th Edition 1-2. A Brief History of Quality  Control and Improvement (Refer to Table 1-1) Walter Shewhart (1924) introduced statistical control chart concepts and QC begins Dodge and Romig (1928), Bell Labs, develop acceptance sampling as an alternate to 100% inspection During WW II the shells didn�t fit the howitzers leading to development of MIL-STDs

33. Introduction to Statistical Quality Control, 4th Edition 1-2. A Brief History of Quality  Control and Improvement (Refer to Table 1-1) The American Society for Quality Control formed in 1946 [now known as the American Society for Quality (ASQ)] 1950s and 1960s saw an increase in reliability engineering, experimental design, and statistical quality control

34. Introduction to Statistical Quality Control, 4th Edition 1-2. A Brief History of Quality  Control and Improvement (Refer to Table 1-1) Competition from foreign industries (Japan) increases during the 1970s and 1980s. Statistical methods for quality improvement use increases in the United States during the 1980s Total Quality Management (TQM) emerges during 1970s and into the 1980s as an important management tool to implement statistical methods.

35. Introduction to Statistical Quality Control, 4th Edition 1-2. A Brief History of Quality  Control and Improvement Malcolm Baldrige National Quality Award is established in 1988. ISO 9000 certification activities increase in U.S. industry in the 1990s. Motorola�s Six-Sigma initiative begins in the 1990s.

36. Introduction to Statistical Quality Control, 4th Edition 1-3. Statistical Methods for Quality Control and Improvement Three major areas: Statistical process control (SPC) Design of experiments (DOE) Acceptance sampling

37. Introduction to Statistical Quality Control, 4th Edition 1-3. Statistical Methods for Quality Control and Improvement Statistical Process Control (SPC) Control charts are used for process monitoring and variability reduction. SPC is an on-line quality control tool.

38. Introduction to Statistical Quality Control, 4th Edition 1-3. Statistical Methods for Quality Control and Improvement Design of Experiments Experimental design is an approach to systematically varying the controllable input factors in the process then determining the effect these factors have on the output responses. Experimental designs are off-line quality tools. Crucial for variability reduction.

39. Introduction to Statistical Quality Control, 4th Edition 1-3. Statistical Methods for Quality Control and Improvement Acceptance Sampling Acceptance sampling is the inspection and classification of a sample of the product selected at random from a larger batch or lot and the ultimate decision about disposition of the lot. Two types: 1. Outgoing inspection - follows production 2. Incoming inspection - before use in production

40. Introduction to Statistical Quality Control, 4th Edition Quality cannot be inspected into the product When the organization realizes this, process improvement efforts begin

41. Introduction to Statistical Quality Control, 4th Edition The objective Systematic reduction of variability First, by using acceptance sampling Then, by using SPC Finally, by using DOE We don�t stop when requirements are met Further reductions in variability lead to better performance Avoid the Taurus transmission

42. Introduction to Statistical Quality Control, 4th Edition 1-4. Other Aspects of Quality  Control and Improvement Total Quality Management (TQM) TQM is a managerial framework to accomplish quality improvement. Other names and related approaches: Company-Wide Quality Control (CWQC) Total Quality Assurance (TQA) Six-Sigma

43. Introduction to Statistical Quality Control, 4th Edition 1-4. Other Aspects of Quality  Control and Improvement 1-4.1 Quality Philosophy and Management Strategies 1-4.2 The Link Between Quality and Productivity 1-4.3 Quality Costs 1-4.4 Legal Aspects of Quality 1-4.5 Implementing Quality Improvement

44. Introduction to Statistical Quality Control, 4th Edition 1-4.1 Quality Philosophy and  Management Strategies Three Important Leaders W. Edwards Deming - Emphasis on statistical methods in quality improvement Joseph Juran - Emphasis on managerial role in quality implementation Armand V. Feigenbaum - Emphasis on organizational structure

45. Introduction to Statistical Quality Control, 4th Edition W. Edwards Deming After WW II, he consulted with Japanese industries Demanded management commitment to use statistical methods Deming Prize in Japan For quality improvement Deming was a harsh critic of US management practices

46. Introduction to Statistical Quality Control, 4th Edition 1. Create a constancy of purpose Focus on the improvement of products and services Constantly improve product design and performance Invest in R&D Innovate

47. Introduction to Statistical Quality Control, 4th Edition 2. Adopt a new philosophy Eliminate defective products It costs as much to produce a defective unit as a good one Dealing with scrap and rework is very expensive

48. Introduction to Statistical Quality Control, 4th Edition 3. Don�t rely on inspection Inspection only sorts out defectives Already have paid to produce them Inspection is too late in the process It�s also ineffective Prevent defectives through process improvement

49. Introduction to Statistical Quality Control, 4th Edition 4. Don�t award business on price alone Consider supplier quality as well Give preference to those suppliers that demonstrate process control and process capability

50. Introduction to Statistical Quality Control, 4th Edition 5. Focus on continuous improvement Involve the workforce Use statistical techniques

51. Introduction to Statistical Quality Control, 4th Edition 6. Invest in training Everyone should be trained in the technical aspects of their job, QC, and process improvement Workers should be encouraged to put this training to use

52. Introduction to Statistical Quality Control, 4th Edition 7. Practice modern supervision methods Help the employees improve the system in which they work

53. Introduction to Statistical Quality Control, 4th Edition 8. Drive out fear Create an environment where the workers will ask questions, report problems, or point out conditions that are barriers to quality

54. Introduction to Statistical Quality Control, 4th Edition 9. Break down the barriers Break down the barriers between the functional areas of the business Only through teamwork can quality and process improvement take place

55. Introduction to Statistical Quality Control, 4th Edition 10. Eliminate targets and slogans Useless without a plan for the achievement of the target or goal Instead, improve the system and provide information on that

56. Introduction to Statistical Quality Control, 4th Edition 11. Eliminate quotas Numerical quotas and work standards often conflict with quality control

57. Introduction to Statistical Quality Control, 4th Edition 12. Encourage employees to do their job Remove the barriers Listen to the workers The person doing the job knows more about it than anyone else

58. Introduction to Statistical Quality Control, 4th Edition 13. Have ongoing education and training Teach them simple yet powerful statistical techniques Use the basic SPC tools, particularly the control chart

59. Introduction to Statistical Quality Control, 4th Edition 14. Involve top management Management should be advocates for these points

60. Introduction to Statistical Quality Control, 4th Edition Dr. Joseph Juran A founder of SQC Co-author of QC Handbook (1957) His philosophy is based on management of the quality function Says that 80% of the opportunities for quality improvement can be addressed by management and only 20% by the workers

61. Introduction to Statistical Quality Control, 4th Edition Dr. Armand Feigenbaum Total Quality Control (1951) Concern is with organizational structure to improve quality Says that QC should be concentrated in a specialized department Conflicts with Deming on this point

62. Introduction to Statistical Quality Control, 4th Edition 1-4.1 Quality Philosophy and  Management Strategies Total Quality Management (TQM) Quality Standards and Registration ISO 9000 Six Sigma Just-In-Time, Lean Manufacturing, Poka-Yoke, etc.

63. Introduction to Statistical Quality Control, 4th Edition TQM Began in the early 80s based on the philosophies of Deming and Juran Evolved into wide spectrum of ideas Participation in quality groups Work culture Customer focus Supplier quality improvement Cross-functional teams concerned with quality

64. Introduction to Statistical Quality Control, 4th Edition TQM A success? Moderately Why not? Not enough concern for reduction of variability Ineffective training conducted by HR people No knowledge of what is important Success measured by % of workforce trained Management not committed

65. Introduction to Statistical Quality Control, 4th Edition TQM More reasons for lack of success Zero defects, value engineering, quality is free Programs with no emphasis on reducing variability

66. Introduction to Statistical Quality Control, 4th Edition ISO 9000 Quality system oriented Say what you do, do what you say Much effort devoted to paperwork and bookkeeping Not much to reducing variability and improving processes

67. Introduction to Statistical Quality Control, 4th Edition ISO 9000 paragraphs 1. Management responsibility for quality 2. Design control 3. Document and data control 4. Purchasing and contract management 5. Product identification and traceability 6. Inspection and testing, including control of measurement and inspection equipment

68. Introduction to Statistical Quality Control, 4th Edition ISO 9000 paragraphs 7. Process control 8. Handling of nonconforming product 9. Handling, storage, packaging and delivery of product 10. Control of quality records 11. Internal audits 12. Training 13. Statistical methodology

69. Introduction to Statistical Quality Control, 4th Edition ISO 9000 US$40 billion annual business worldwide Registrars, auditors, consultants Plus, 1000s of hours of internal costs Effective? Does it reduce variability?

70. Introduction to Statistical Quality Control, 4th Edition Six Sigma Developed by Motorola in the late 80s Consider that + 3s provides 0.00135 in each tail, or 0.00270 in the two tales So, in 1 million parts, 2700 would be defective

71. Introduction to Statistical Quality Control, 4th Edition Six Sigma Consider an assembly of 100 parts that must all function for the assembly to function .9973 x .9973 x �..9973 = (.9973)100 = .7631 Thus, about 23.7% of the products under 3s will fail Not usually an acceptable situation

72. Introduction to Statistical Quality Control, 4th Edition Six Sigma But, + 6s results in 0.999999998 inside specs (0.999999998)100 = .9999998 Or, 2 parts/billion defective i.e., 0.2 ppm Much better than + 3s

73. Introduction to Statistical Quality Control, 4th Edition Six Sigma Has moved beyond Motorola Has come to encompass much more Has become a method for improving corporate business performance Companies involved in Six Sigma use teams that work on projects involving quality and costs

74. Introduction to Statistical Quality Control, 4th Edition Six Sigma More successful than TQM More managerial commitment Involves costs But, it�s still another slogan and program Better to train everyone in quality tools and make efforts to reduce variability

75. Introduction to Statistical Quality Control, 4th Edition JIT, Lean Manufacturing, etc. Programs that devote too little attention to variance reduction For example, JIT The variability in demand results in a need for inventory Reduce the variability and reduce the inventory

76. Introduction to Statistical Quality Control, 4th Edition 1-4.2 The Link Between Quality and Productivity Effective quality improvement can be instrumental in increasing productivity and reducing cost. The cost of achieving quality improvements and increased productivity is often negligible.

77. Introduction to Statistical Quality Control, 4th Edition An example Data 100 parts/day are manufactured 75% are conforming 60% of the nonconforming can be reworked for a cost of $4 Remainder are scrapped Direct manufacturing cost is $20/part

78. Introduction to Statistical Quality Control, 4th Edition An example Cost/conforming part [$20 (100) + $4 (15)]/90 = $22.89 Note that the yield is 90 conforming/day

79. Introduction to Statistical Quality Control, 4th Edition An example New process us introduced Fallout is 5% 60% can be reworked Cost/conforming part [$20 (100) + $4 (3)]/98 = $20.53 Note that the yield is 98 conforming/day Up from 90/day And, costs are reduced by 10.3%

80. Introduction to Statistical Quality Control, 4th Edition 1-4.3 Quality Costs Quality Costs are those categories of costs that are associated with producing, identifying, avoiding, or repairing products that do not meet requirements. These costs are: Prevention Costs Appraisal Costs Internal Failure Costs External Failure Costs

81. Introduction to Statistical Quality Control, 4th Edition Quality costs Prevention costs Quality planning and engineering New products review Product/process design Burn-in Training Quality data acquisition and analysis

82. Introduction to Statistical Quality Control, 4th Edition Appraisal costs Inspection and test of incoming material Product inspection and test Materials and services consumed Maintaining accuracy of test equipment

83. Introduction to Statistical Quality Control, 4th Edition Internal failure costs Scrap Rework Retest Failure analysis Downtime Yield losses Downgrading (off-specing)

84. Introduction to Statistical Quality Control, 4th Edition External failure costs Complaint adjustment Returned product/material Warranty charges Liability costs Indirect costs

85. Introduction to Statistical Quality Control, 4th Edition Pareto analysis Cost reduction through identifying improvement opportunities Identifying quality costs by category, or by product, or by type of defect or nonconformity

86. Introduction to Statistical Quality Control, 4th Edition Monthly quality costs for PCB assembly

87. Introduction to Statistical Quality Control, 4th Edition Pareto analysis Insufficient solder 42% of defects and 52% of scrap and rework costs Work on that defect first Most of the cost reductions will come from attacking the few problems that are responsible for the majority of the quality costs

88. Introduction to Statistical Quality Control, 4th Edition Appraisal or prevention Many firms spend far too much of their quality management budget on appraisal and not enough on prevention Money spent on prevention has a much better payoff than money spent on appraisal

89. Introduction to Statistical Quality Control, 4th Edition 1-4.4 Legal Aspects of Quality The re-emergence of quality assurance as an important business strategy is in part a result of Consumerism Product Liability

90. Introduction to Statistical Quality Control, 4th Edition Consumerism Virtually every product line of today is superior to that of yesterday But, many consumers see it otherwise Consumer tolerance for minor defects & aesthetic problems has decreased considerably Blemishes, surface-finish defects, noises, appearance problems

91. Introduction to Statistical Quality Control, 4th Edition Consumerism Many manufacturers introduce new designs before they are fully evaluated and tested To remain competitive Unproved designs

92. Introduction to Statistical Quality Control, 4th Edition Product liability Manufacturers and sellers are likely to incur a liability when they have been unreasonably careless or negligent in what they have designed, or produced, or how they have produced it

93. Introduction to Statistical Quality Control, 4th Edition More stringent: Strict liability 1. There is a strong responsibility for both manufacturer and merchandiser requiring immediate responsiveness to unsatisfactory quality through product service, repair, or replacement of defective product Extends into the period of use by the consumer By producing the product, manufacturer and seller must accept responsibility for use

94. Introduction to Statistical Quality Control, 4th Edition More stringent: Strict liability 2. All advertising statements must be supportable by valid company quality or certification data

95. Introduction to Statistical Quality Control, 4th Edition 1-4.5 Implementing Quality Improvement Strategic management of quality Almost all successful efforts have been management-driven. Too much emphasis on registration and certification programs (ISO, QS) Insufficient focus on quality planning and design, quality improvement, overemphasis on quality assurance Poor use of available resources

96. Introduction to Statistical Quality Control, 4th Edition End