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SIX SIGMA

ANKIT VIJAYVARGIYA

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What is Six Sigma?Six Sigma is a highlydisciplined process that helps us focus on developing and delivering near-perfect productsand services.Why ”Sigma“? The word is a statistical term that measures how far a givenprocess deviates from perfection. The central idea behind Six Sigma is that if you canmeasure how many “defects” you have in a process, you can systematically figure out howto eliminate them and get as close to “zero defects” as possible.

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Sigma (σ)

A term used in statistics to represent standard deviation, an indicator of the degree of variation in a set of measurements or a process. A one-sigma process produces 691462.5 defects per million opportunities—a percentage of satisfactory outputs of only 30.854%.

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Standard deviation

A measure of the spread of data points in relation to the mean. It’s the most common measure of variation in a set of data

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Six Sigma

A philosophy of managing that focuses on eliminating defects through practices that emphasize understanding, measuring, and improving processes. It’s based on the statistical concept of six sigma, measuring a process at only 3.4 defects per million opportunities (DPMO).

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DPMO at sigma levels

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HISTORICAL PERSPECTIVE ON SIX SIGMA

In the mid-1980s, Motorola, under the leadership of Robert W. Galvin, was the initial developer of Six Sigma. Most credit the late Bill Smith for inventing Six Sigma; Smith, a senior engineer and scientist with n Motorola’s Communications Division, had noted that its final product tests had not predicted the high level of system failure rates Motorola was experiencing. He suggested that the increasing level of complexity of the system and the resulting high number of opportunities for failure could be possible causes for this. He came to the conclusion that Motorola needed to require a higher level of internal quality, and he brought this idea to then-CEO Bob Galvin’s attention, persuading him that Six Sigma should be set as a quality goal.

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Six Sigma: DMAIC

Methodology• Define• Measure• Analyze• Improve• Control

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Define Key Items

• Customers, Value, Problem Statement • Scope, Timeline, Team• Primary/Secondary & OpEx Metrics• Current Value Stream Map• Voice Of Customer (QFD)

(Quality Function Deployment)

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Measure

• Establish measurement capability• Validate the database (transactional)• Gage R&R (Repeatability & Reproducibility)• Calibration is not enough• Many (or most) measurement systems are

not capable• How good is the data you are using to

make decisions?

• Fix the measurement system• Enables calculation of process capability• Enables calculation of alpha & beta risks

• This step is often skipped

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Analyze(and fix the obvious)

• Find all KPOVs & KPIVs(Key Process Output Variables; Key Process

Input Variables)• FMEA, DOE, critical Xs, VA/NVA

(Failure Modes Effects Analysis; Design Of Experiment)

• Graphical Analysis, ANOVA(Analysis Of Variance)

• Future Value Stream Map

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Improve

• Optimize KPOVs & test the KPIVs(Key Process Output Variables; Key Process

Input Variables)• Redesign process, set pacemaker• 5S, Cell design, MRS

(Material Replenishment System)• Visual controls• Value Stream Plan

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Control

• Management of Change• Owned by project champion and value

stream manager• Critical to long term success of project• Physical and cultural changes

• Measurement controls• On-going metrics

• Visual Controls• Enable workers to self-manage the process

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Next Project

DefineCustomers, Value, Problem Statement

Scope, Timeline, Team

Primary/Secondary & OpEx Metrics

Current Value Stream Map

Voice Of Customer (QFD)

MeasureAssess specification / Demand

Measurement Capability (Gage R&R)

Correct the measurement system

Process map, Spaghetti, Time obs.

Measure OVs & IVs / Queues

Analyze (and fix the obvious)Root Cause (Pareto, C&E, brainstorm)

Find all KPOVs & KPIVs

FMEA, DOE, critical Xs, VA/NVA

Graphical Analysis, ANOVA

Future Value Stream Map

ImproveOptimize KPOVs & test the KPIVs

Redesign process, set pacemaker

5S, Cell design, MRS

Visual controls

Value Stream Plan

ControlDocument process (WIs, Std Work)

Mistake proof, TT sheet, CI List

Analyze change in metrics

Value Stream Review

Prepare final report

Validate Project $

Validate Project $

Validate Project $

Validate Project $

Celebrate Project $

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• Develop a focused Problem Statement and Objective• Develop a Process Map and/or FMEA• Develop a Current State Map• Identify the response variable(s) and how to measure them• Analyze measurement system capability• Assess the specification (Is one in place? Is it the right one?)

Practical Problem

ProblemDefinition

• Characterize the response, look at the raw data• Abnormal? Other Clues? Mean or Variance problem?

• Time Observation • Spaghetti Diagram • Takt Time• Future State Maps • Percent Loading • Standard Work Combination• Use Graphical Analysis, Multi-Vari, ANOVA and basic

statistical tools to identify the likely families of variability

ProblemSolution

• Identify the likely X’s• 5S • Set Up Time Reduction (SMED)• Material Replenishment Systems• Level Loading / Line Leveling• Cell Design • Visual Controls• Use Design of Experiments to find the critical few X’s• Move the distribution; Shrink the spread; Confirm the results

Problem Control

• Mistake Proof the process (Poka-Yoke)

• Tolerance the process• Measure the final capability• Place appropriate process controls on

the critical X’s• Document the effort and results• Standard Work • TPM

IdentifyProblem

• Strategic Link to Business Plan defined in Project Selection Process• Defined Business Impact with Op Ex Champion support• Structured Brainstorming at all organizational levels• Cause and Effect Diagrams identifying critical factors• Primary and Secondary Metrics defined and charted• Multi-Level Pareto Charts to confirm project focus

Plan Execute

Execute Plan

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Breakthrough performance gains

2 308,5373 66,8074 6,2105 2336 3.4

2 308,5373 66,8074 6,2105 2336 3.4

PPMPPM

(Distribution Shifted ± 1.5)

ProcessCapability

ProcessCapability

Defects per Million Opportunities

Defects per Million Opportunities

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Basic ImplementationRoadmap

Understand and DefineEntire Value Streams

Deploy Key Business Objectives- Measure and target (metrics)

- Align and involve all employees- Develop and motivate

Define, Measure, Analyze, ImproveIdentify root causes, prioritize, eliminate waste,

make things flow and pulled by customers

Control-Sustain Improvement

-Drive Towards Perfection

Identify Customer Requirements

Vision (Strategic Business Plan)

Continuous Improvement (DMAIC)

Identify Customer Requirements

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The Normal Curve and Capability

LSL USL

Poor Process Capability

Very High Probability of Defects

LSL USL

Excellent Process

Capability

Very Low Probability of Defects

Very High Probability of Defects

Very Low Probability of Defects

Low SigmaLow Sigma High SigmaHigh Sigma

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What about Lean, TOC, TQM

• Six Sigma• Remove defects, minimize variance

• Lean• Remove waste, shorten the flow

• TOC• Remove and manage constraints

• TQM• Continuous Improvement

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Does it work?.

Source: American Customer Satisfaction Index, U Michigan, HBR, 2001

199973

companies

Ralston Purina

Quaker OatsHilton Hotels

Coca-ColaUnilever

etc.

The top companies in Customer Satisfaction grow MVA atnearly twice the rate of their poor-performing counterparts.

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Customer Satisfaction Index Score

Mar

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