Chapter 1

Introduction

Introduction

• Using statistical methods to improve quality– Identifying trouble spots and their causes– Predicting major problems

• Quality: Fitness for use– Meeting the needs of the marketplace– Dynamic nature

• Quality: Variability – To reduce variability– To hit the target

1.1 Quality and Productivity

• Misconception: inverse relationship between productivity and quality

• Reduction in non-conformities• Reduction in rework• Eliminating complexity in the workplace (late

delivery…)

1.2 Quality Costs

Cost of Achieving Good Quality– Prevention costs

• Quality planning costs• Product design costs• Process costs• Training costs• Information costs

– Appraisal costs • Inspection and testing• Test equipment costs• Operator costs

Cost of Poor Quality– Internal failure costs

• Scrap costs• Rework costs• Process failure costs

(Diagnostic)• Process downtime costs• Price-downgrading costs

– External failure costs • Customer complaint costs• Product return costs• Warranty claims costs• Product liability costs• Lost sales costs

• Break-even charts

Increasing Quality

$

Failure Cost

Appraisal Cost

Total Quality Cost

Quality Improvement and Quality Cost

Prevention Cost

1.2 Quality Costs

• Other considerations:– Sales– Customers’ perceptions– Market competition

1.3 Need for Statistical Methods

• Statistical techniques are needed:– To determine if abnormal variation has occurred– To determine changes in the values of process

parameters– To identify factors that are influencing process

characteristics

1.4 Early Use of Statistical Methods for Improving Quality

• Contribution to WWII• American Society for Quality Control (ASQC),

1946– American Society for Quality (ASQ), 1997

• Industrial Quality Control, first issue in July 1944– Journal of Quality Technology– Quality Progress

1.5 Influential Quality Experts

• Walter A. Shewhart (1891~1967)– Shewhart charts

• W. Edwards Deming (1900~1993)– Japanese progress– 14 points for management– PDCA (Plan-Do-Check-Act) cycle

• PDSA (Plan-Do-Study-Act) cycle

1.5 Influential Quality Experts

• Walter A. Shewhart (1891~1967)– Shewhart charts

• W. Edwards Deming (1900~1993)– Japanese progress– 14 points for management– PDCA (Plan-Do-Check-Act) cycle

• PDSA (Plan-Do-Study-Act) cycle

Deming's 14 points for Management

1. Create a constancy of purpose toward product improvement to achieve long-term organizational goals.

2. Adopt a new philosophy of preventing poor-quality products instead of acceptable levels of poor quality as necessary to compete internationally.

3. Cease dependence on inspection by relying instead on statistical quality control to improve product and process design.

4. Work constantly to improve the system.

Deming's 14 points for Management

5. Break down barriers between departments, and promote cooperation and a team approach for working together.

6. Do not award business to suppliers solely the basis of price.

7. Drive out fear.8. Eliminate numerical goals, targets, and slogans. 9. Eliminate work standards and substitute

leadership.10.Institute a program of training and education

for all employees.

Deming's 14 points for Management

11. Institute modern training methods of quality improvement throughout the organization, from top management down, so that continuous improvement can occur.

12. Remove the barriers that make it difficult for employees to do their jobs.

13. Institute and practice modern methods of supervision.

14. Create a management climate that will facilitate the attainment of these objectives.

1.5 Influential Quality Experts

• Joseph M. Juran (1904~2008)– Quality management– Juran’s Quality Control Handbook

• Eugene L. Grant (1897~1996)– Teaching of SQC– Statistical Quality Control, 1946

• Harold F. Dodge (1893~1976)– Acceptance sampling– Consultant to the Secretary of War (WWII)

• George E.P. Box (1919~ )– Control charts and process control in tandem

SOFTWARE APPLICATIONS

• Excel• MINITAB