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claculation of DPPM

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  • #35753

    Yadav
    Participant

    Dear Sir’s
     
    I have heard a lot about PPM. But sorry to say that I don’t know how to calculate the same in SMT industry. Please let me kanow abou the same. Please revert.

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    #101244

    Gabriel
    Participant

    I don’t know what is SMT, but the calculation of PPM is allways the same:
    1) Count all parts
    2) Inspect all parts
    3) Count defective parts
    4) PPM=1,000,000 * defective parts / all parts

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    #101278

    Yadwadkar
    Participant

    PPM formula will be always same, but for SMT industry specific requirements you can refer IPC standards.
    May be IPC – 9261 will help you.
    Mahendra

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    #101282

    SSNewby
    Member

    I am assuming that you refer to surface mount technology when you say SMT, and I agree with your previous two posters.   Your calculations are the same regardless of the technology at play, and the IPC standards – probably IPC 610 (E – I think it is now) give you the defect types impacting both internal and external acceptance of your process/product.  You will/can get into an endless circular debate regarding defects on your surface mounted chip, is it one lead solder defective out of many on a chip at issue or is it a process defect to have one on the board/final assembly – the main thing is to assure criteria selection consistency between the numerator and denominator for your calculation, make it meaningful and stick with it.  Benchmark within your industry.  If you need more detail, please ask – I had some fun years in aerospace engineering and operations prior to medical products.   Good luck.

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    #101285

    Savage
    Participant

    IPC-7912 and IPC-9261 call out the industry standards for how to use and calculate various metrics for the SMT world.
    It directs you on calculating DPMO, DPPM (PPM), OMI (Overall Manufacturing Index), yields, etc.  They are decent manuals.  Check them out.

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    #101342

    Hmnnn…
    Participant
Viewing 6 posts - 1 through 6 (of 6 total)

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