IE 331 Statistical Quality Control Prepared by Dr. Mohamed Abdel Fattah Sharaf King Saud university...

IE 331

Statistical Quality Control

Prepared byDr. Mohamed Abdel Fattah Sharaf

King Saud universityCollege of engineering

Industrial engineering Department

Part 1

Concepts of Quality

The Dialectic of Quality

A continuous learning cycle: thesis meets antithesis and creates synthesis.

Product Standards

Statistical Methods

Quality Control

CustomerFocus

QualityAssurance

HumanFactors

QualityEngineering

ProcessAnalysis

QualityManagement

SystemsEngineering

Six

Sigma

Traditional Definition

Quality means “fitness for use”

•Quality of design •Size, Power, Materials

•Quality of conformance (meeting specs)• Manufacturing process

• Training/supervision

A Better Definition

Quality means “fulfilling customer expectation” •Allows for comparison of different items

•Places the customer as the judge •Eliminates focus on meeting specs

So What Do Customers Want?

•PERFECT! –Defect free

•FREE! –Low cost

•NOW!

Quality Costs

Quality Costs

• Prevention costs: process/product design, training, vendor relations;

• Appraisal costs: quality audits, statistical quality control;

• Correction costs (internal failure): yield losses, rework charges;

• Recovery costs (external failure): returns, repairs, lost business.

Costs associated with quality:Costs associated with quality:

The Value Equation

price

yFlexibilitTimelinessQualityValue

Quality

Why Quality is Critical

Why Quality is Critical• Quality: Quality is the single most important thing

you can work on to improve the effectiveness of your company. It's as simple as that. Things just cascade when you get control of your quality. John Young, CEO Hewlett Packard

• Micro-economic interpretation:

Quantity

Price Demand Supply

Quality affects both!

The Competition• The Japanese are headed for world quality leadership and

will attain it in the next two decades because no one else is moving there at the same pace. J.M Juran, 1967

• IBM decided to have some parts manufactured in Japan as a trial project. In the specifications, they set the limit of defective parts at three units per 10,000. When the shipment arrived from Japan, it included this letter:

“We Japanese have hard time understanding North American business practices. But the three defective parts per 10,000 have been included and are wrapped separately. Hope this pleases.”

Toronto Sun

Dimensions of Quality

Eight Dimensions of Quality

• 1. Performance– the primary operating characteristics of the product or service.

• 2. Features– the characteristics that supplement the basic functioning of the

product or service.

• 3. Reliability– probability of the product or service failing within a specified

period of time.

• 4. Conformance– the degree to which a product or service meets acknowledged

standards

Eight Dimensions of Quality

• 5. Durability– a measure of product life (both technical and economic).

• 6. Serviceability– the speed, courtesy, competence, and ease of repair or

recovery.

• 7. Aesthetics– how a product or service looks, feels, sounds, tastes, or smells.

• 8. Perceived Quality– various tangible and intangible aspects of the product from

which quality is inferred.

Service Quality

Dimensions of Service Quality

• Tangibles– Appearance of facilities, equipment, personnel…

• Reliability– Promised service dependably and accurately

• Responsiveness– Willingness to help, prompt service

• Assurance– Knowledge, courtesy, trust, confidence

• Empathy– Caring, individualized attention

Service Quality Gap Model

Five ways service quality can fail...

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Gap 1

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Gap 1

2

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Gap 1

2

3

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Gap 1

2

3

4

Service Quality Gap Model

Service Quality Gap Model

Word of Mouth Personal Needs Past Experience

Expected Service

Perceived Service

Service Delivery

Translate Perceptionsto Specifications

Perceptions ofCustomer Expectations

External Communications

Customer

Organization

Gap 1

2

5

3

4

Quality Pioneers

Quality Pioneers & GurusQuality Pioneers & Gurus

• Early American Industry Pioneers– Walter Shewhart–Control Charts– Dodge & Romig–Acceptance Sampling– Arnold Feigenbaum–Total Quality Management

• Post W.W.II / Japanese Quality Gurus– W. Edwards Deming–Total Quality Management– Joseph Juran–The cost of quality– Philip B. Crosby–Quality is free– Masaaki Imai–Kaizen– Kaoru Ishikawa–TQM-Japanese style

Deming

W. Edwards Deming

• 1900 to 1993

• Trained as a physicist

• Master of Science -- CU

• Taught SQC during World War II

• Went to Japan in 1946

• Brought SQC to Japan

• Enthusiastically adopted by Japanese

Deming’s Theory of Quality & Economics

Improve Quality

Costs decrease because of less rework, fewer mistakes, fewer delays, snags; better use of machine-time and

materials

Productivity Improves

Capture the market with

better quality and lower price

Stay in business

Provide jobs and more jobs

Deming’s 14 Points

1. Constancy of purpose

2. New philosophy

3. Cease inspection

4. Move beyond price

5. Improve constantly

6. Job training

7. Modern supervision

8. Drive out fear9. Break down barriers10.Eliminate slogans…11.Eliminate quotas12.Promote pride13.Education &

retraining14.Top management

commitment

Deming Improvement Cycle

Act Plan

DoCheck

Deming Improvement Cycle

Act

Plan

Do

Check

Continuous Improvement

ActPlan

Do

CheckA

ctP

lanDo

Check

Japanese Deming Prize

• Established 1951• Annual prize• Awarded for

– development of quality tools, or– quality improvement programs

• Created by JUSA(Union of Japanese Scientists and Engineers