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Any Advice re Defect Rate % for Rolled Goods or Cut Parts

Six Sigma – iSixSigma Forums Operations Manufacturing Any Advice re Defect Rate % for Rolled Goods or Cut Parts

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  • #55572

    Big Red
    Participant

    I’m looking to use OEE. I’m wondering how others handle calculating defect rate % for rolled goods, extrusion processes, or die cut parts.

    Example put in 100kgs get out 1,0000 meters.
    Issue 400meters of material, get out 4500 discrete parts.

    Is it a % change from standards? Advice would be appreciated.

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    #200571

    Chris Seider
    Participant

    If you have a theoretical standard for getting X parts out of meters of material, then your quality number could be X created / (Y meters * Z theor parts/meter). Some will tell you they recommend the standard parts/meter but often that standard is a deflated balloon because wastes become part of that standard.

    Remember the trend is most important for your OEE so create a standard and move on.

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    #200573

    Big Red
    Participant

    Great point about waste getting pulled into standards. I’m curious for those living in a highly digitized mfg. environment what data/info you would maintain to conduct this calculation.
    I need to manage ~150 Sku’s that have vastly different BOMs and BORs. What an expected output is on any given day depends on the mix. Given systems such as ERP,MRP,MES and STS solutions, how does one maintain values that help systems like planning and scheduling be predictable, but yet we don’t pull waste into the values used there for purposes of calculating Defect rate % when theoretical standards are needed?

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    #200574

    MBBinWI
    Participant

    @lonkelm – as my friend @cseider says, do not remove unused material from the calculation. This will cause the defect rate, particularly for nested material, to be lower than other types of production that do not have inherent waste. There is no way to perfectly nest cut parts, so some waste is inevitable. However, leaving the waste included in the defect number will continue to challenge the organization to find more optimal methods to reduce this waste. Different sheet sizes, dynamic nesting routines, etc.

    As for the rolled product, ensure that you get actual material input. This may require that you go back to the original raw material put into the furnace, as measuring a pour is more challenging.

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