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Quality Management


Definitions

J. M. Juran defined quality as “fitness for purpose.” Philip Crosby defined quality as “conformance to specifications.”

A. V. Feigenbaum defines Total Quality Control (TQC) as:“Total quality control is an effective system for integrating the quality-development, quality-maintenance, and quality-improvement efforts of the various groups in an organization so as to enable marketing, engineering, production, and service at the most economical levels which allow for full customer satisfaction.”


Various Dimensions of Quality

Various Dimensions of Quality

Safety – How much care the company has taken to make the product safe for users before, during, or after use? For example, a TV having features to protect eyes of viewers from harmful radiations.

Appearance – How pleasant is the outward look, smell, taste, feel, or sound of the product to the customers? For example, a super-thin flat TV (which can be hung on a wall like a picture)

Performance –How well does the product perform with respect to its intended use? For examplegood picture and sound effects of a TV.

Features – What special features does the product have? For example, 1200 watt sound system, flat-picture tube, picture-in-picture feature, etc. in a TV.

Serviceability – How easily, cheaply, and speedily can the product be repaired and serviced? For example, a company providing on-the-spot repairs of TV within one hour of customer complaint at nominal charges.

Durability – How long can the product perform before needing any repair or replacement of parts? For example, a TV gives best performance for 10 years without needing any repair.

Reliability – How much is the probability of breakdowns, need for adjustments, replacement of parts, etc. in the product? For example, a TV performing well every time it is switched on.

Customer Service – How is the behavior and treatment of the seller with the customer before, during and after the sale of the product? E.g. the pleasant treatment given by the sales staff prompted a customer to buy another TV of the same brand from the same dealer.


Cost of prevention of defects – training &

performing Acceptance Sampling of raw

materials, SQC, Six Sigma and other

techniques

Costs of Quality

Costs of Quality

Cost of warranty claims – This

includes the loss of goodwill on part of

customers

Cost of detecting defects in the final product-

Outgoing inspection of products before being shipped to customers

Cost of scrap and rework of defective

products – this includes the extra paper work, delays, rescheduling

required etc.


Deming’s Contribution to Total Quality Management

• Consistency of purpose is a must for continual improvement of the product.

• Continuous change and innovation is a must for survival.

• Quality cannot be achieved only by inspection. • Eliminate wastes in every functional area, not only

production. • Attitude of supervisors and managers towards

workers should be that of a facilitator.• Remove the barriers between departments and

individuals.• Posters and slogans should be eliminated.


Deming’s Contribution to Total Quality Management

• Remove obstacles in the good workmanship of hourly workers to instill a sense of pride in them.

• Vigorous programmes of retraining and education of employees are a must.

• Top management’s commitment for ever-improving quality is a must.

• Numerical targets and work standards may affect quality.

• Encourage workers to give quality improvement ideas without fear.

• On-the-job training of employees is a must• Lowest price should not be the criteria for selecting

a supplier.


Quality at Every Stage

Transformation process

Feedback Mechanisms

INPUTS OUTPUTS

Random disturbances

Monitoring Quality Levels at Every Stage of the Transformation Process

Quality of inputs monitored

(Acceptance Sampling)

Quality of outputs monitored

(Acceptance Sampling)

Statistical Process Control (SPC)


Statistical Process Control

6.95 mm

7.05 mm

Central Line (CL)

Upper Specification Limit (USL)

Upper Control Limit (UCL)

Lower Control Limit (LCL)

Lower Specification Limit (LSL)

Specification & Control Limits for the Diameter of a Pencil

M - 3.σM

M + 3.σM

Targeted or Aimed-at Mean M = 7.00 mm


Type I and Type II Errors

Process is in control

Process is out of control

Search for assignable causes is

done

Search for assignable causes is not done

Type I error

Type II error

Correct approach

Correct approach

Type I & Type II errors


Trends in µ chart suggesting out-of-control situation

LCL

UCL

CL

UCL

LCL

CL

UCL

LCL

CL

Trends in μ chart suggesting out of control situation

Time

Time

Time

A point exceeding the LCL (or UCL) A decreasing (or increasing) trend of 7 or 8 successive points

5 or more successive points on one side of the CL

Upper Control Limit (UCL)

Lower Control Limit (LCL)

Upper Warning Limit (UWL)

Lower Warning Limit (LWL)

Central Line (CL)

μ + 3.sμ μ + 2.sμ

μ - 3.sμ

μ - 2.sμ

μ

Warning Limits in μ chart (two out of three successive points beyond a warning limit suggest an out of control situation)


Process Capability Ratio

3s1 3s1

3s2 3s2

3s3 3s3

LSL USL CL

LNTL

LNTL

LNTL

UNTL

UNTL

UNTL

Effect of decreasing Process Capability Ratio (PCR)

Situation A

Situation B

Situation C

Defective items Defective items

Defective itemsDefective items


Process Capability Ratio for an Off-Center Process

3s 3s

3s 3s

3s 3s

LSL = μ - 3 s = 6.957674

USL= μ + 3 s = 7.046747

CL = 7.002211

LNTL

LNTL

LNTL

UNTL

UNTL

UNTL

Effect of Shift in the Process Mean

Defective items

Defective items

Defective itemsDefective items

μ

μ’

μ’’

μ + 1.5 s = 7.024479

μ - 1.5 s = 6.979943

Part C

Part B

Part A


Taguchi’s Cost of Variability

LSL USL

Incremental cost of

variability

High

Traditional & Taguchi’s Views of Cost of Variability

0 Target or aimed-at

value

Taguchi’s quality loss

function

Traditional view


Six Sigma

μ

μ

μ + 3.sμ - 3.s

μ + 6.s’μ - 6.s’

LSL USL CL

s

s’

Three Sigma quality level

Six Sigma quality level

Defective items

Defective items

Defective items

Defective items


Steps in Implementing Six Sigma

DMAIC

• Step 1 – Define: Define the priorities of the customers with respect to quality

• Step 2 – Measure : Measure the processes and the defects arising in the product due to the process

• Step 3 – Analyze: Analyze the process to determine the most likely causes of defects

• Step 4 – Improve : Improve the performance of the process and remove the causes of the defects

• Step 5 – Control : Ensure that the improvements are maintained over time.


Contrasting Six Sigma and TQM

Six Sigma• Executive ownership• Business strategy

execution system• Truly cross functional• Focused training with

verifiable return on investment

• Business results oriented

TQM• Self-directed work teams• Quality initiative • Largely within a single

function• No mass training in

statistics and quality with return on investment

• Quality oriented


Acceptance Sampling

0.000 0.010 0.020 0.030 0.040 0.050 0.060 0.070 0.080 0.090 0.100 0.110 0.120

0.2000

0.4000

0.6000

0.8000

1.0000 � ��

�

�

�

�

�

�

�

�

��

1.0000 0.99940.9834

0.9161

0.7851

0.6160

0.4457

0.3007

0.1912

0.1157

0.06710.0375

0.0203

Operating Characteristics (OC) Curve


ISO 9000

• ISO 9001: This is the most comprehensive of the certificates for an organization engaging in development / design, production, installation, and servicing

• ISO 9002: This certification is provided to organizations involved only in production and installation of products/services

• ISO 9003: This certification is provided to organizations involved only in final inspection and testing

Two documents are provided by ISO as guidance to organizations for understanding various aspects of a good quality system:

• ISO 9000: This document explains principal concepts and applications, guide to selection and use.

• ISO 9004: This document explains principal concepts and applications, guide to quality management, and quality system elements.


ISO 14001

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