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Topic FTY=e-DPU


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This topic contains 11 replies, has 9 voices, and was last updated by  Mike Carnell 3 years, 2 months ago.

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  • #168485 Reply

    I am confused as to how to obtain the FTY using a constant e-2.718 can someone enlighten me?


    FTY= e -DPU
    FTY=2.718 -0.3

    How did this get calculated? HELP!

    #168495 Reply

    Do some research on the Poisson equation, this site or elsewhere.

    #168498 Reply

    Reputation - 0
    Rank - Aluminum

    True, also needed a elaborated question. Self study here, will save you time.

    #168504 Reply

    I believe this formula is referring to RTY not FTY if memory serves, and obtaining it involves simply taking the natural log (e^x) of the negative dpu measure. – it took me three key strokes on the calculator.

    #206569 Reply

    Reputation - 40
    Rank - Aluminum

    just one state RTY=FTY if defect=0
    and as I know RTY= e -DPU when we would like to calculate as a short term but long term you should to multiplication every DPU for each process.

    #486265 Reply

    B Cox

    You probably already figured this out, but … The exercise to figure FTY uses an exponent for DPU, expressed as a negative. So your expression
    FTY= e (constant) -DPU (to the power expressed)
    FTY=2.718 -0.3 (power of negative .3)
    I don’t have a scientific calculator so I used Excel, where the formula is shown as “=POWER(2.718,-0.3)”

    #486281 Reply

    It’s RTY….not FTY.

    #486289 Reply

    ….well Chris, I suppose if the production line was moving really fast you might be able to get the product airborne in which case it would be flying and not rolling…. :-)

    #486355 Reply


    How about this kind of flying item?

    #486383 Reply

    @rbutler – Good one, Robert. You’re getting punnier, and punnier all the time!

    @cseider – One of the more bizzaro sitcoms – even for its day. Seriously, the lift to weight ratio for a habit that size would at best lift a midget, I don’t care how little Sally Field weighed. And no vertical stabilizers? Please, totally aerodynamically infeasible, totally unstable (but then, maybe that was a metaphor for Sally?).

    #493314 Reply



    FTY=e-DPU (e minus DPU or e raised to the negative power of DPU)
    RTY=e-total DPU (e minus total DPU)
    DPU=-ln(FTY) (negative logarithm of FTY)
    e= 2.718 which is a constant value.
    Example:- If DPU is 0.008928571 then (if you calculate in Excel) FTY = =POWER(2.718,-0.008928571) = 0.991111663 or 99.11%.
    DPU=-ln(FTY),(if you calculate in Excel)=-LN(0.991111663
    Also calculate p(d) probability of defets and find Z value from Z table.

    p(d) = 1-Yield.

    #493378 Reply

    @cjdawgct As several people have tried to explain this is an estimate of Rolled Throughput Yield. It is an estimate. The higher the defect level the less accurate the estimate. Once you are over a 10% defect level it is probably inaccurate enough that you wouldn’t want to use it.

    When you are getting stats advice from @cseider, @MBBinWI and @MBBinWI to need to pay attention because these guys are very good. When you get stats advice from @rbutler it isn’t going to get any better even if you pay for it.

    Just my opinion.

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