Download - Six Sigma - Understanding basic concepts

  • Six Sigma - Understanding basic concepts

  • Business Relevance of 6Improvement(in Qly, Cost, Del & Serv.)Maintenance(Old Products & Services)CustomerGovt. PoliciesSubstitutionCompetition

  • Gap analysis Dos & NeedsSupplierCustomerDefect Free Cost Cycle Time Quality Price DeliveryDosGaps to be addressed continuouslyNeeds

  • Six sigma Simple concept6 is a level of performance that reduces the defects in products & services significantlyA set of statistical tools that helps to measure, analyse, improve and control processes.A commitment to customers to achieve an acceptable level of performanceMind Set + Tool Set = Six

  • 6 Sigma ThemeCustomer focussedProcesses are key driversFact driven and Proactive for creativityResult oriented - demands financial analysis to verify gains

  • 6 Sigma ThemeVoice of Customer (VOC): Specs decided by customers (Dependent variable, say Y)- Response time; TAT; Breakdowns; Product performance, waiting time at ATM/counter etc.Voice of Process (VOP): Variability of a process; Process variations cause defects (Independent variable, say x)

  • 6 Sigma Quality ThemeSix Sigma QualityHitting the Target(Centralise the Process)Elimination of Process variabilityProcess should be with minimum variability and on the target

  • What does 6 Sigma do?Real life problemStatistical solutionStatistical problemReal life solutionYyy = f(xi)

  • 6 Sigma Steps - RDMAIC

  • 6 Sigma Steps - RDMAICTo identify the major business issuesTo recognise key processes that need improvementAreas that need break throughsIdentify critical to customer (CTC)Drill down to CTQ (translating expectations to parameters); Define specs, UL & LL, TargetsY= f (xi)

  • 6 Sigma Steps - RDMAICTools generally usedQFD MatrixImportance gain matrix

    Project selection criteria high gainlow hanging fruitsUrgencyEfforts required

  • Define the key requirements to customer Customers know their languageListening to customers means understanding their needs.Drill down the CTC6 Sigma Steps - RDMAICCustomer say Engineers say..

    Long life 20,000 Hrs life Reliable 3000 MTBF Comfort cooling 24 1 Deg CDefine step will deliverProject Chartering(Goal, Milestone, Roles)Process Mapping (SIPOC model)

  • Input, Process and output measures are to be defined Measure process stabilityMeasure repeatability and reproducabilityMeasure current process capability

    6 Sigma Steps - RDMAICStandard softwares are availableto process the data

  • Total surface area 100%11111168.26%95.44%Lower ControlLimit99.78%Upper Control LimitX3 Sigma process

  • Customer perceive and registerthe variance more than average

  • 66Lower Spec.XUpper Spec.6 Sigma process (statistical vision)

  • Defects

    Countable failures that are associated with a single unit.A single unit can be defective but may contain more than one defect.Defectives

    Completed units that are classified as bad or not meeting specs. Whole unit is said to be of defective.Defects vs Defectives

  • DPU

    DPU= Defects / unitDPMODPMO = DPU x 1,000,000Opportunities per unit DefectsOpportunities=x 1,000,000= Defects per million opportunitiesTerminologies used

  • Sigma Defects per Million (DPMO)


    3 66,807

    4 6,210

    5 233

    6 3.4 % non-defective

    69.1% 93.32%






    0.023%6 Sigma process (measures)

  • Example 1 :

    52 defects, 250 AMC proposals, 4 defects opportunities / proposal

    DPMO = [(52)/ (250*4)] X 1000000

    = 52,000 = 3.1 Sigma level Example 2 :

    99 defects, 750 products, 150 defects opportunities /productDPMO = [(99)/ (750*150) ]X 1000000

    = 880 = 4.65 Sigma level Traditional approach

    5 applications were rejected (contains 52 defects)

    5/250 = 2% rejectionTraditional approach

    10 products were rejected (contains 99 defects)

    10/750 = 1.33% rejection

  • Software (Minitab) outputs some screens..

  • Software (Minitab) outputs some screens..P > 0.05

    Data follows normal distribution

  • Software (Minitab) outputs some screens..

  • 6 Sigma Steps - RDMAICIdentify cause & effect [ y = f (x) ]Use analytical tools to vital few Short list causes that are vital few which can be taken to improve phase

  • 6 Sigma Steps - RDMAICIdentify and formulate causesQuantify and verify causesIdentify Opportunities process mapping FMEA QFDProcess CapabilityStratification Seven QC tools Why-why analysis BrainstormingIdentify success factor List of opportunities in vital few Hypothesis tests DOEY = f(x1, x2, x3, x4, x5,..xn)

    This s the function that models and quantifies the relationship between X & Y

  • To find out vital causes (x)Optimal value of causesVerify optimal setting with set tolerances6 Sigma Steps - RDMAICDOE is one of the tools used to establish relationship between inputs & outputs

  • Measurement System validation for inputsProcess capability Implementation of SPC Charts6 Sigma Steps - RDMAIC

  • FMEAFMEA is an analytical technique used by designers, engineers and analysts to ensure that all design or manufacturing or process failure modes have been considered and are assessed with a view of elimination. System FMEA Process FMEA Product/Design FMEAWhat is a failure?A component or system not meeting or not functioning as per design (Ex. Break failure)What is a failure mode?The manner in which a component or a system failure occurs (Ex. leakage of break oil )What is an Effect?The impact or consequence of failure (vehicle meeting accident)

  • FMEASeverity of effect? (Scale 1-10)Possibility of failure? (scale 1-10)Possibility of detecting? (scale 1-10)Severity of impactProb. of occurrenceDetectability1. 824Degree of chances that it gets detected before it goes to customerRPN(Risk Priority Number)64(Max 1000, Min 1)2. 469216Work on high RPNReduce severity, rarely changesReduce prob of occurrence (Have parallel system, hand break)Improve detectability (process, tests, reliability)

  • QFDTool used priorities the areas to focus. Customer RequirementsX1X2X3X4X55243134323127516423561HML3257Proj to focusCorrelation between Xs

  • DOEStructured proactive process for finding relationship between input and output factors.

    Multiple input factors are considered and controlled simultaneously to ensure that the effect on the output is significant.Why DOE?

    To find out vital few Xs that influence the quality of Y

    To identify the best combination of values of Xs to get the optimal value of process performance

  • Sigma level - Customer focus

  • Sigma level of different sectors1245673Tax advicePrescriptionwritingRestaurant billPayroll processingAir Lines Baggage handlingBest in ClassAir Lines safety1000,000100,00010010,0001000101Defects in PPM

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