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What is Six Sigma?What is Six Sigma?

Six Sigma is a business strategy that usesstatistical and non-statistical tools andtechniques, change management tools,

project management skills, teamwork skillsand a powerful roadmap to maximize anorganization's return on investment (ROI)through the elimination of defects inprocesses.

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What makes Six Sigma differentWhat makes Six Sigma different

from other quality managementfrom other quality managementinitiatives?initiatives?y Clear focus on achieving measurable and quantifiable financial

returns

y Importance on strong and passionate leadership

y Integrates human elements (culture change, customer focus,

belt system infrastructure, etc.) and process elements(process management, statistical analysis of process data,

measurement system analysis, etc.) of improvement

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y Utilizes the tools and techniques for fixing problems in business

processes in a sequential and disciplined fashion

y Creates an infrastructure of Champions, Master Black Belts

(MBBs), Black Belts (BBs) and Green Belts that lead, deploy and

implement the approach

y Utilizes the concept of statistical thinking and encourages the

application of well-proven statistical tools and techniques for

defect reduction through process variability reduction methods

What makes Six Sigma differentWhat makes Six Sigma different

from other quality managementfrom other quality managementinitiatives?initiatives?

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Benefits of Six SigmaBenefits of Six Sigma

y Effective management decisions due to heavy reliance

on data and facts instead of gut-feelings and

y Increased understanding of customer needs and

expectations

y Increased cash flow by making processes more

efficient and reliable

y Improved knowledge across the organization on

various tools and techniques for problem-solving

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y Reduced number of non-value-added operations

through systematic elimination, leading to faster

delivery of service, faster lead time to production,

faster cycle time

y Reduced variability in process performance, product

capability and reliability, service delivery and

performance

y Transformation of organizational culture from being

reactive to proactive thinking or mindset

Benefits of Six SigmaBenefits of Six Sigma

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Six Sigma MethodologySix Sigma Methodology

Five-stage methodology:

y Define phase - involves identifying a project's CTQ (critical-to-

quality) characteristics driven by the voice of the customer

y Measurement phase - identify the key internal processes that

influence CTQ characteristics and measures the defects currently

generated

y Analysis phase - establish process capability and define

performance objectives by benchmarking and identifying the

sources of variation

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Five-stage methodology:

y Improvement phase - confirm the key

variables or causes and quantifies their

effects on the CTQs

y Control phase - develop corrective actions,

new standards and procedures, finalizedocumentation and share the key lessons

learned from the project

Six Sigma MethodologySix Sigma Methodology

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ASPIRE and Six Sigma at TataASPIRE and Six Sigma at Tata

SteelSteely Until 2002, Tata Steel was following a modular framework

that used numerous tools and techniques to bring about

process improvements

y Numerous process/performance improvement techniques

and models, such as VE, ISO, QIP, TBEM, etc., were adopted

over the years. But they did not have a perspective or

organized framework that would guarantee that the problem

solutions developed were the best or most optimal ones.Also, due to the localized and contextual nature, the leverage

of solutions developed for one problem was not available for

other similar problems

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y In order to address this issue and providean integrated framework Six Sigma

methodology was started in June 2002

y It was later merged with other initiativeslike total productive maintenance (TPM),

5S, value engineering (VE), Poka-Yoka,theory of constraints and named asASPIRE (Aspirational Initiatives to RetainExcellence).

ASPIRE and Six Sigma at TataASPIRE and Six Sigma at Tata

SteelSteel

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ASPIRE DMAIC methodology (DMAIC, DefineASPIRE DMAIC methodology (DMAIC, Define--MeasureMeasure--AnalyzeAnalyze--ImplementImplement--Control) was deployed atControl) was deployed atTata SteelTata Steel

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Need for ASPIRE DMAIC approachNeed for ASPIRE DMAIC approach

y For the production of 1 ton of hot metal

400500 kg of coke is required

y Coke is produced by carbonization of

coal at about 10001100C

y The coke so produced then undergoes a

quenching process.

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y A need was felt to bring about improvementin the average levels of residual cokemoisture achieved as well as keeping its

standard deviation low

y A large number of improvement projectstaken in the past but these projects had not

been able to make a permanent impact onthe intended objectives. Therefore, thisprocess was chosen for ASPIRE DMAICapproach for improvement

Need for ASPIRE DMAIC approachNeed for ASPIRE DMAIC approach

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ASPIRE DMAIC approach forASPIRE DMAIC approach for

improvementimprovement in the average levelsin the average levelsof residual coke moistureof residual coke moisturey Define phase - the CTQ identified was

moisture % in coke and moisture content in

coke should never be more than 3.5%y Measure phase

a) Measurement of coke moisture was carriedout every shift by recording the loss in weight

of the sample during testingb) A Gage R&R study was used to validate themeasurement system

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Average coke moisture from yearAverage coke moisture from year

1999 February to 2002 February1999 February to 2002 February

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y Analyze phase -a) The upper specification limit of cokemoisture was defined as 3.5%

b) A target was taken to improve thesigma level of moisture up to3 (corresponding to 6.7% defect)

c) To improve the coke moisture someproblem areas were identified afterbrainstorming and these were analyzedwith the help of a failure modes andeffects analysis' (FMEA)

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FMEA performed onFMEA performed on

quenchingquenchingProcess/operation/function

Failure

mode

Effect of

failureSeverity Causes Occurrence Control Detectability

Quenching Inconsisten

cy in flow

rate

Different

amount of

water used

4 Different water

level in quenching

tank

7 No control 8

Leakage of

water

Extra water

added

6 Leakage from dry

fog nozzles, flap

sealing, sprayingvalve

5 Time-to-time

maintenance

5

Double

quenching/s

potquenching

Excess

moisture in

coke

8 Initial quenching

not proper, faulty

parameter design

9 By experience 6

Non-

uniformdistributionof coke on

quenching

car

Hot coke in the

wharf

7 No

synchronizationof speed betweenloco and pusher

ram

8 Controlled by

skill level ofoperator

7

Water

carry over

in thewharf by

quenching

car

Higher

moisture

7 Improper drain-

out, improper

parameter design

5 By experience 6

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d) Factors that impact the moisture level incoke were identified. After a detailed analysis,

three critical parameters were shortlisted: Quenching time

Crack opening time

Drain-out time

y Improve phase

Once the parameters were finalized theoptimal combinations of these parametersfor getting lower average value and standarddeviation of the coke moisture weredetermined.

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Control phase

a) After implementing the best possiblecombination the challenge was to make theperformance of coke moisture consistent

b) the average value of coke moistureimproved from a base value of 3.432.7%.Standard deviation of coke moisture alsoimproved from 0.9 to 0.44

c) To sustain the improvement in the longrun a rigorous automated controlmechanism was followed

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THANK YOU

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