1DSCI 3123

Quality Management and SQC

• Outline Quality Control– Definition of Quality– Commonly Used Terms– TQM– Seven QC tools– Variance reduction– Control Charts

2DSCI 3123

Definition of Quality

• Fitness for use - J.M. Juran

• Conformance to requirements - P.B. Crosby

• Meets expectations of the customer - A. Feigenbaum

• The totality of features and characteristics of a product or service that bear on its ability to satisfy given needs

- ANSI/ASQC

3DSCI 3123

Terms Commonly Used

• Statistical Quality Control

• TQM

• Design of experiments

• Control Charts

• Deming’s 14 points

• ISO 9000 Certification

4DSCI 3123

Deming

• Overall philosophy embodied in 14 points

• Promoted employee empowerment

• Encouraged worker training

• Developed PDCA Cycle– Plan– Do– Check– Act

1. Plan

2. Do3. Check

4. Act

5DSCI 3123

TQM

• Initiated by Feigenbaum, Total Quality Control

• Idea reflecting total organizational commitment to quality

• Referred to as continuous quality improvement

• Total Quality Management today

• Buzz-word all over Corporate America

6DSCI 3123

TQM Principles

• Customer defines quality

• Top management must lead effort

• View quality as a strategic issue

• Quality is everyone’s responsibility

• Focus on continuous quality improvement

• Employees/Management must cooperate to establish quality

• Use Statistical quality control methods

• Training and education are fundamental to all the above

7DSCI 3123

Seven QC Tools

• Flowcharts - i.e., how a process flows

1 2 3 4

1a

yes

no

8DSCI 3123

Seven QC Tools

• Pareto Diagrams - measures the distribution of quality losses

A B C D E

61%

4%5%13%

17%

% E

RR

OR

S

9DSCI 3123

Seven QC Tools

• Histograms - a graphic summary of dispersion

5 10 15 20 25

Num

ber

0

10

2

0

30

4

0

|

|

|

| Suggested Mean

Length

10DSCI 3123

Seven QC Tools

• Scatter Diagrams - depict relationships between paired data

5 10 15 20 25

Num

ber

0

10

2

0

30

4

0

|

|

|

| Linear Relationship - possible high r value

11DSCI 3123

Seven QC Tools

• Cause and Effect Diagram

Product Quality

Order Fulfillment

Service

Distribution System

Order Processing System

Customers are dissatisfied

12DSCI 3123

Seven QC Tools

• Run Charts– Run charts are used to detect trends or patterns– Same model as scatter plots

• Control Charts– Run charts turn into control charts– One of the single most effective quality control

devices for managers and employees

13DSCI 3123

Control Chart

• Periodic tracking of a process

• Common types– Xbar, R or range, p or percent nonconforming

• Elements of a control chart– upper control limit (UCL), the highest value a process should

produce

– central line (Xbar), the average value of consecutive samples

– lower control limit (LCL), the lowest value a process should produce

14DSCI 3123

Control Charts - Xbar

• Shows average outputs of a process

UCL

LCL

Central line- Xbar

Sca

le

15DSCI 3123

Control Charts - R

• Shows the uniformity/dispersion of the processUCL

LCL

Central line- Rbar

Sca

le