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Is Zero Defects Really Possible?

Six Sigma – iSixSigma Forums General Forums Methodology Is Zero Defects Really Possible?

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  • #55257

    Brian
    Participant

    Is the goal of Zero Defects really Posibile and will the cost justify the means?

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    #199367

    Chris Seider
    Participant

    If one can poka yoke the defect from getting to the customer or shut down the process if an X get’s out of range, yes zero defects is possible for SOME scenarios.

    Yes, in the case of customers not receiving defects, there’s still the opportunity for rework or yield loss–I’m not discounting this opportunity but it’s possible to have a downstream process or customer “see” zero defects.

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    #199368

    JB
    Participant

    Some really smart guy said “quality is free”.

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    #199378

    Brian
    Participant

    JRB,
    Who was this really smart guy?

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    #199380

    Strayer
    Participant

    Philip B. Crosby in his book “Quality is Free” asserted that the cost of a defect always exceeds the cost of preventing it — preventing it, not finding and fixing it after it occurs — therefore quality is free. Statistically, zero defects is not possible. Statistics deals with probabilities. Even if we get beyond 6 sigma (3.4 or fewer defects per million opportunities) we don’t get to zero probability. Crosby and others point out that zero defects is nonetheless the only appropriate goal. If we say we want to achieve 6 sigma we’re saying we want to create 3.4 defects per million. Why would we want to do that?

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    #199384

    Srikar
    Participant

    When you are talking about “some” scenarios, do you think achieving such an environment comes with a lot of initial cost?

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    #199386

    Srikar
    Participant

    forgot to mention the tag @cseider. the above question was for you :)

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    #199388

    Norbert Feher
    Participant

    I agree with @cseider.

    The key is to consider alternate solutions and apply 7 ways metholody for example to select the best one. Even a soft poka yoke could be changed for a hard one with additional thought…

    In case of companies I work for people very often stop by improving detection capabilities (FMEA) only but that should be a short term solution especially if that requires human involvement. By improving detection root cause is still not solved and this has to be the long term goal…

    It was also interesting to see that sometimes the best poka yoke solutions were implemented by the workers instead of the engineers.

    Final thought:
    stop in case of abnormality is also a very important step toward zero defect production…

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    #199389

    JB
    Participant

    I agree with what @straydog says regarding the probability of zero defects. However, as an individual customer, I can certainly have a “zero defect experience”, and even multiples of them in a row. I have one every time I stop by my favorite pub.

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    #199415

    Suraj Singh
    Guest

    Man himself is biggest pokayoke as per TPS.!!! so special cause & comman cause occurs so zero defect is not possible to achieve.

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    #199417

    Chris Seider
    Participant

    @srikar

    If a poke a yoke is doable, then it’s probably not too expensive by definition. Process improvement must be aligned with business conditions and with alignment with the process management.

    I’d never argue for something that only has a return on investment of 1% but I’d say something has to improve the situation and look for alternatives.

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