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Six Sigma

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Dilbert

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Introduction

6σ : new world

σ is the symbol for the standard deviation.

6σ is equivalent with 3.4 defects per million opportunities.

Hooving 30 m2 on 6σ -level means only 1 cm2 missed.1/3.4 million part of the day equals 0.29 second1/3.4 million part of the equator of the earth equals about 140 meter.

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Statistical background

+/− 3σ

+/− 6σ

Nominal=µ

LSL USLT olerance

ppm0.001 ppm

1350ppm1350

ppm0.001

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Statistical background

LSL

0 ppm ppm3.4

1.5σ

T oleranceUSL

ppm3.4ppm

66803

µ

+/ − 6σ

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What is Six Sigma?

Simple– Eliminate defects– Eliminate the opportunity to have defects

Complex– Vision– Metric (Standard measuring method)– Benchmark– Philosofy– Method– Tool for:

> Customer satisfaction> ‘Breakthrough’ improvements> Continuous improvement> Employee involvement

– Agressive goals

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Six Sigma is everywhere

Six Sigma Methods Production

DesignService

Purchase

HRM

Administration

QualityDepart.

Management

M & S

IT

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Uniform standard‘Sigma’-metric

23456

3085376680762102333.4

σ PPM69.1%93.3%99.38%99.977%99.9997%

Yield

Process Defects permillion

Long termyield

Current standard

World class

performance

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Financially interesting

Benefits of 6σ approach w.r.t. financials

σ-level Defect rate (ppm)

Costs of poor quality Status of the company

6 3.4 < 10% of turnover World class 5 233 10-15% of turnover 4 6210 15-20% of turnover Current standard3 66807 20-30% of turnover 2 308537 30-40% of turnover Bankruptcy

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Why improvement?

RedoWaste

RedoWaste

InputInput Processstep

Processstep InspectionInspection

The hidden factory

goodproductsgood

products ClientClient

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Six Sigma

• Motorola (1987)• Texas Intruments en DEC (1988)• IBM (1989)• AlliedSignal en Kodak (1994)• General Electric (1995)• Whirlpool, Bombardier en Polaroid (1996)• Sony, Citibank (1997)• Paccar-DAF Trucks, Black & Decker (1998)• Perlos, American Express (1999)• Ford (2000)

• Motorola (1987)• Texas Intruments en DEC (1988)• IBM (1989)• AlliedSignal en Kodak (1994)• General Electric (1995)• Whirlpool, Bombardier en Polaroid (1996)• Sony, Citibank (1997)• Paccar-DAF Trucks, Black & Decker (1998)• Perlos, American Express (1999)• Ford (2000)

Companies implementing Six SigmaCompanies implementing Six Sigma

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Six Sigma

A scientific and practical method to achieve improvements in a company

Scientific:• Structured approach.• Assuming quantitative data.

Practical:• Emphasis on financial result.• Start with the voice of the customer.

”Show me the money”

“Show me the data”

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Method

Define Select a project

Measure Make concrete the project

Analyse Characterise the current situation

Improve Optimise the process

Control Assure the improvements

DMAIC

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MethodFocus on the process:

Y = f(X1, X2, …, Xn)

OutputProcess Inputs

Caffeine% = f(DCM, time to extract, number of extracts, temperature, …)

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New way?

Approach to improve

Praktical problem Statistical problem

Y = f(X1, X2, …, Xn)

Praktical solution Statistical solution

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Define

Projects may be selected according to:

1. A complete list of requirements of customers.

2. A complete list of costs of poor quality.

3. A complete list of existing problems or targets.

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Priorities

1

1. Requirements,2. Costs,3. Problems.

1.Collect data

2 3

3.Give priority-Financial benefits-Expected throughput time of the project-Severity of the problem

2.Arrange the information

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Six Sigma

Characteristics involved

Y = f(X1, X2, …, Xn)

Critical to Quality (External)Critical to Quality (Internal) Influence factors:

• Process parameters• Disturbances• Noise variables

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Example

RoastRoast

Coffeebeans

CoolCool

GrindGrindMoisture contentPackPack

Sealed coffee

Moisture content

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Measure

MeasureMeasure

Concrete the problem:• Establish how to measure in the

process;• Investigate the demands (USL,

LSL);• Evaluate the measurement method.

Concrete the problem:• Establish how to measure in the

process;• Investigate the demands (USL,

LSL);• Evaluate the measurement method.

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Measure

4.54.0☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺

USLUSL

Moisture%Moisture%

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Analyse

AnalyseAnalyse

Study the current performance of the process:

• Determine the kind of problem;• Identify the influence factors.

Study the current performance of the process:

• Determine the kind of problem;• Identify the influence factors.

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Analyse

2 0 01 5 01 0 05 0

2 0 01 5 01 0 05 0

To run experiments oneneeds a process which is

in statistical control.

SPC

DoE

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FMEA,Data

Multi-vari,Trendgraph

Testing-theory

Control chart,Cp, Cpk

Uncontrolled processes Controlled processes

Process Capabilitystudy

FMEA,Control chart

IdentifyX’s

IdentifyX’s

SelectX’s

SelectX’s

Improve Improvements Experiment

Assure,Control loop

Control

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3.2 3.7 4.2 4.7 5.2

USLUSL

Process Capability Analysis for Vocht%

USLTargetLSLMeanSample NStDev (ST)StDev (LT)

CpCPUCPLCpkCpm

PpPPUPPLPpk

PPM < LSLPPM > USLPPM Total

PPM < LSLPPM > USLPPM Total

PPM < LSLPPM > USLPPM Total

4.50000 * *

3.91502500

0.1777310.193639

*1.10

*1.10

*

*1.01

*1.01

*10000.0010000.00

* 498.51 498.51

* 1259.86 1259.86

Process Data

Potential (ST) Capability

Overall (LT) Capability Observed Performance Expected ST Performance Expected LT Performance

STLT

☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺ ☺☺

Waste!

Analyse

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0 10 20 30 40 50

3.2

4.2

5.2

Observation Number

Indi

vidu

al V

alue

Regelkaart voor Vocht%

11

1

X=3.900

3.0SL=4.410

-3.0SL=3.390

Analyse

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AnalyseUSLUSL

USLUSL

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Three types of influence factors

Caffeine content of Extracted coffee

Caffeine%raw coffee

Stuffed-upfilterTime to extract

ProcessparameterProcessparameter

May be used to control.

May be used to control.

Noise variableNoise variable DisturbanceUndesirable sources of variation.

Undesirable sources of variation.

Disturbance

Outliers, incidentsOutliers, incidents

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Improve

ImproveImprove

Run a statistical experiment:• Determine which influence factors

are really important;• Model the relationship with the

CTQ.

Run a statistical experiment:• Determine which influence factors

are really important;• Model the relationship with the

CTQ.

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110105

600

3.5 Bluswater

4.0

100610

4.5

5.0

620 630

Vocht%

95640Gewicht

110105

600

3.5 Bluswater

4.0

100610

4.5

5.0

620 630

Vocht%

95640Gewicht

3.85 4.10 4.35 4.60 4.85

600 610 620 630 640

95

100

105

110

Gewicht

Blus

wat

er

Contour Plot of Vocht%

3.85 4.10 4.35 4.60 4.85

600 610 620 630 640

95

100

105

110

Gewicht

Blus

wat

er

Contour Plot of Vocht%

Improve

Moisture% = –16.57 + 0.023×B + 0.025×G – 0.0003×B×GMoisture% = –16.57 + 0.023×B + 0.025×G – 0.0003×B×G

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Control

ControlControl

Implement improvements:• Use the relationship to define an

optimal process;• Design a system to assure the

improvements.

Implement improvements:• Use the relationship to define an

optimal process;• Design a system to assure the

improvements.

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Control

3.2 3.7 4.2 4.7 5.2

USLUSL

Process Capability Analysis for Vocht%

STLT

BeforeBefore

σ = 0.19σ = 0.19

AfterAfter

σ = 0.04σ = 0.04

USL

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Organisation

Yellow Belts

Master Black Belts

GreenBelts

GreenBelts

Black Belts

GreenBelts

GreenBelts

Black Belts

GreenBelts

GreenBelts

Black Belts

Six SigmaChampions

CEO

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Persons

ChampionChampion

• Belongs to management• Selects projects • Gives priority• Solves bottlenecks• Is willing to change• Has social skills• 1 day training• Is responsible for the BB project w.r.t. the

organisation

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Persons

Black BeltBlack Belt

• Belongs to the middle management• Is well-educated• Project is related to daily activities• May prioritise his work• Enough motivation• Willing to change• Has good social skills

Improvement potential: € 50 000

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BB training

DefineThroughput time projectThroughput time project

4 months (full time)4 months (full time)Measure

Training (1 week)Training (1 week)

Work on project(3 weeks)

Work on project(3 weeks)

ReviewReview

Analyse

Improve

Control