chapter 10 - managing quality

8/13/2019 Chapter 10 - Managing Quality

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Chapter 10

Principles of

Six Sigma

MANAGING FOR QUALITY ANDPERFORMANCE EXCELLENCE, 7e, 2008Thomson Higher Education Publishing

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Key Idea


Although we view quality improvementtools and techniques from theperspective of Six Sigma, it is importantto understand that they are simply acollection of methods that have beenused successfully in all types of quality

management and improvementinitiatives, from generic TQM efforts, toISO 9000, and in Baldrige processes.


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Six-Sigma Metrics

Defect any mistake or error that ispassed on to a customer

Defects per unit (DPU) = number ofdefects discovered number of unitsproduced

Defects per million opportunities (dpmo) =

DPU 1,000,000 opportunities for error



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Six-Sigma Quality

Ensuring that process variation is half thedesign tolerance (Cp = 2.0) while allowingthe mean to shift as much as 1.5 standarddeviations, resulting in at most 3.4 dpmo.


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Key Idea


Although originally developed formanufacturing in the context of tolerance-

based specifications, the Six Sigmaconcept has been operationalized to applyto any process and has come to signify ageneric quality level of at most 3.4 defectsper million opportunities.


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k-Sigma Quality Levels



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Problem Solving

Problem: any deviation between what shouldbe and what is that is important enough to

need correcting Structured Semistructured Ill-structured

Problem Solving: the activity associated withchanging the state of what is to what shouldbe

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Key Factors in Six Sigma ProjectSelection

Financial return, as measured by costs associatedwith quality and process performance, and

impacts on revenues and market share Impacts on customers and organizational

effectiveness Probability of success Impact on employees Fit to strategy and competitive advantage



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Problem Solving Process

1. Redefining and analyzing the problem2. Generating ideas

3. Evaluating and selecting ideas4. Implementing ideas



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Key Idea


A structured problem-solving processprovides all employees with a commonlanguage and a set of tools tocommunicate with each other,particularly as members of cross-

functional teams.


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Common Six Sigma Tools



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Define

Describe the problem in operational terms Drill down to a specific problem statement

(project scoping) Identify customers and CTQs, performance

metrics, and cost/revenue implications



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Measure

Key data collection questions

What questions are we trying to answer? What type of data will we need to answer the

question? Where can we find the data? Who can provide the data? How can we collect the data with minimum effort

and with minimum chance of error?

MANAGING FOR QUALITY ANDPERFORMANCE EXCELLENCE, 7e, 2008

Thomson Higher Education Publishing


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Improve

Idea generation Brainstorming Evaluation and selection Implementation planning




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Control

Maintain improvements Standard operating procedures Training Checklist or reviews Statistical process control charts




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Tools for Six-Sigma and Quality

Improvement Elementary statistics Advanced statistics Product design and reliability Measurement Process control

Process improvement Implementation and teamwork




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Design for Six Sigma

Focus on optimizing product and processperformance Features

A high-level architectural view of the design

Use of CTQs with well-defined technical requirements Application of statistical modeling and simulation

approaches Predicting defects, avoiding defects, and performance

prediction using analysis methods Examining the full range of product performance

using variation analysis of subsystems andcomponents




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Key Idea



All Six Sigma projects have three keycharacteristics: a problem to be solved,a process in which the problem exists,and one or more measures that quantifythe gap to be closed and can be used to

monitor progress.


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Key Six Sigma Metrics in Services

Accuracy Cycle time Cost Customer satisfaction




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Lean Production and Six Sigma The 5Ss: seiri (sort), seiton (set in order), seiso

(shine), seiketsu (standardize), and shitsuke (sustain). Visual controls

Efficient layout and standardized work Pull production Single minute exchange of dies (SMED) Total productive maintenance Source inspection Continuous improvement




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Traditional Economic Model ofQuality of Conformance



Total cost

Cost due tononconformance

Cost ofquality

assurance

optimal level of quality 100%


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Modern Economic Model of Qualityof Conformance


Total cost

Cost due tononconformance

Cost of

qualityassurance

100%

chapter 10 - managing quality

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