Quality Management

© Holmes Miller 1999

Based on slides for Chase Acquilano and Jacobs, Operations Management, McGraw-Hill

Definitions of Quality

ASQC: Product characteristics & features that affect customer satisfaction

User-Based: What consumer says it isManufacturing-Based: Degree to which a

product conforms to design specificationProduct-Based: Level of measurable

product characteristicExercise: List attributes of a quality

car

Importance of QualityCosts & market share

Market GainsReputationVolumePrice

Lower CostsProductivityRework/ScrapWarranty

ImprovedQuality

IncreasedProfits

Total Quality Management

Managing the entire organization so that it excels on all dimensions of products and services that are important to the customer.Involves entire organization from supplier to

customerObjective: Meet or exceed customer needs

through company-wide continuous improvement

Early proponentsW. Edwards DemingJ. M. JuranPhilip B. Crosby

Some Total Quality Management Principles

Continuous improvementEmployee empowermentBenchmarkingKnowledge of TQM tools

1. Plan a change aimed at improvement.

1. Plan

2. Execute the change.

2. Do

3. Study the results; did it work?

3. Check

4. Implement the change; abandon it or do it again.

4. Act

CI Methodology: PDCA Cycle (Deming Wheel)

Employee Empowerment

Getting employees involved in product & process improvements85% of quality problems are due to process &

material Techniques

Talk to workersSupport workersLet workers make decisionsBuild teams & quality circles

Benchmarking

Learn “best practices”Form Benchmarking teamsHow might Muhlenberg go about

benchmarking? What topic might be “benchmarked”?

Quality Tools

Quality function deployment (QFD)Taguchi techniquesPareto chartsProcess chartsCause & effect diagrams Statistical process control (SPC)

Pareto Chart

Vertical bar chart showing relative importance of problems or defects Makes identifying & solving them easier

Based on Pareto PrincipleMost effects have relatively few causese.g., 80% of quality problems come from 20%

of machines, materials, or operatorsFocus on ‘vital few’ 20% causesCalled 80-20 rule

Process Chart Example

SUBJECT: Request tool purchase

Dist (ft) Time (min) Symbol Description

D Write order

On desk

75 D To buyer

D Examine

SUBJECT: Request tool purchase

Dist (ft) Time (min) Symbol Description

D Write order

On desk

75 D To buyer

D Examine

= Operation; = Operation; = Transport; = Transport; = Inspect; = Inspect; D = Delay; D = Delay; = Storage = Storage

Cause & Effect Diagram Example

MethodMethod ManpowerManpower

MaterialMaterial MachineryMachinery

DrillDrillDrillDrillOverOverOverOverTimeTimeTimeTime

SteelSteelSteelSteel

WoodWoodWoodWood

LatheLatheLatheLathe

TiredTiredTiredTired

Too many defects

Too many defects

OldOldOldOld

SlowSlowSlowSlow

ExerciseIn your group, select a problem:

At MuhlenbergYour companyAnother organization

Develop a cause and effect diagram to address the problem

Deliverable: Develop the diagram and share solution with class

Statistical Process Control (SPC)

Uses statistics & control charts to tell when to adjust process

Developed by Shewhart in 1920’sInvolves

Creating standards (upper & lower limits)Measuring sample output (e.g. mean weight)Taking corrective action (if necessary)

Done while product is being produced

970

980

990

1000

1010

1020

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

LCL

UCL

Can be used to monitor ongoing production process quality and quality conformance to stated standards of quality.

Can be used to monitor ongoing production process quality and quality conformance to stated standards of quality.

Example: Control Charts

Aspects of Statistical Process Control

Process VariationKey Point: ANY process has associated

variationProcess Capability

Some processes are not capable of satisfying customer requirements

Process Control ProceduresVariable data

72” in height, 131 lbs.Attribute data

On/Off, 7 scratches on surface

SPC at Honda

Basic Forms of Variation

Assignable variation is caused by factors that can be clearly identified and possibly managedtemporary employeeimproperly set machine

Common variation is inherent in the production processphone system cannot handle incoming traffic

-- slow response times

SPC at Honda (Part 2)

Six Sigma Quality

A philosophy and set of methods companies use to eliminate defects in their products and processes

Seeks to reduce variation in the processes that lead to product defects

The name, “six sigma” refers to the variation that exists within plus or minus six standard deviations of the process outputs

Six Sigma allows managers to readily describe process performance using a common metric: Defects Per Million Opportunities (DPMO)

1,000,000 x

units of No. x

unit per error for

iesopportunit ofNumber

defects ofNumber

DPMO 1,000,000 x

units of No. x

unit per error for

iesopportunit ofNumber

defects ofNumber

DPMO

Six Sigma Quality: DMAIC Cycle

Define, Measure, Analyze, Improve, and Control (DMAIC)

Developed by General Electric as a means of focusing effort on quality using a methodological approach

Overall focus of the methodology is to understand and achieve what the customer wants

Inspection

Involves examining items to see if an item is good or defective

Objective: Detect a defective productDoes not correct deficiencies in process or

productIssues

When to inspectWhere in process to inspectConsider Transformation Process ---

Transformation Process -- Revised View

Inputs Transformation Process Outputs Customer

Inspect Inspect Warranty

Good- will

Rework Scrap

These are the additional costs of quality!

CONTROL CHARTS

External Failure Costs

Appraisal Costs

Prevention Costs

Internal FailureCosts

Costs ofQuality

Costs of Quality

Funnel Experiment (Deming)Treating a special cause as a common cause Improvement of a stable system nearly always

means reduction of variation -- -- it may also require moving the center line to

a higher or lower level.Tampering with a stable system only increases

the production of faulty items and mistakes.One necessary qualification of anyone in

management is -- -- stop asking people to explain ups and downs

that come from random variation.