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Human Process Sigma Expectation

Six Sigma – iSixSigma Forums Old Forums General Human Process Sigma Expectation

  • This topic has 5 replies, 4 voices, and was last updated 14 years ago by AC.
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  • #48841

    Ropp
    Participant

    Does anyone know of a Sigma Expectation for a Human Process?

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    #165688

    Adam L Bowden
    Participant

    Are you asking about:Typical errors – 1 key stroke error in 200Typical Sigma – I used to know this number – I think it peaked at
    about 3.5 Sigma – perhaps some one else can shed light on this
    more specifically.Typically though you have to “mistake proof” or automate to take
    quality to the next level.Adam

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    #165691

    Ropp
    Participant

    That is exactly what I am looking for.  How much variation and error should I expect from a process that is completed by a human.  Example, a human installs 300,000 screws per shift with a defect rate or 900.  A robot installs 300,000 screws per shift with a defect rate of 1.  Is the human process at it’s expected sigma rate?  Is it worth the time and effort to try to improve the human sigma rate?  By 1%?  10?
    What is an expected sigma rate for a human process?  Is there back up for this figure?

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    #165695

    Adam L Bowden
    Participant

    Well – it’s always good to drive improvements by semi or full
    automation. But over the last 15 or 20 years there is a shift, due to
    “effectiveness” from dedicated robot assembly to more flexible
    semi-automation.
    Even more important is using the defect data to not only drive DFSS
    but to focus on re-design to minimize defects. I.e if a screw is
    driven into a thread but at an angle it will strip the threads or jam
    causing a defective “mating surface”. If the assembly is re-
    designed a “plot hole” may be cast in to guide the screw to
    eliminate the potential for miss-alignment.I think we can all get anal and into analysis paralysis but have to
    step back at times and look at the big picture and see if changing
    the design or process is a better avenue rather than trying to
    mistake proof a poor design.Regards,Adam

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    #165699

    gembaguy
    Participant

    Some automation is ok, but if you completely remove the human from the process you also lose the brain that can see how to improve that process (see AutoNOmation)…

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    #165702

    AC
    Participant

    Without knowing what type of process you are trying to bechmark, it is difficult to give estimate definite human factor sigma level.  The 3.5 sigma is a generic benchmark for developed manufacturing processes. 
    Also, automation doesn’t come without some baggage of it’s own.  Difficulty of implementation, cost, reliability (weibull curve of reliability), and lack of ingenuity in the product are just some reasons to consider fully automating a process.
    I agree with gembaguy that although automation may reduce the defect rate of a certain process, certain goods and services require the

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