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idea for MSA on burr off of Coin op?

Six Sigma – iSixSigma Forums Old Forums General idea for MSA on burr off of Coin op?

Viewing 9 posts - 1 through 9 (of 9 total)
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  • #43722

    Lugbill
    Participant

    I have tried everything from calipers to micrometers to comparators to perfrom a successful MSA on measuring the burr height on a tube of a coin pierce and trim operation.  We have a spec that says we are allowed to have burr less than 10% of material thickness. How can I effectively measure this?

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    #139101

    Haugen
    Participant

    What went wrong with the comparator?  Sounds like a good application for non-contact – comparator, laser, machine vision, etc.  Comes down to a field of view calculation to get the right accuracy/R&R. required for your application – and then proper fixturing and lighting, but there should be multiple companies who can do it if you don’t already have the right equipment.

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    #139114

    Lorax
    Participant

    Weight?

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    #139117

    Lugbill
    Participant

    Part weight is right around a pound. Comparator worked best but still only got 68% part to part variation and two distinct catagories.

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    #139119

    Lorax
    Participant

    Time to annoy HornJM:
    The 10% on the burr, is there a +/- tolerance (actual or implied)? If so, stick it into the Minitab R&R calc and see how the comparator does against that. It may be that the choice of parts on the initial R&R was misrepresenting the part-to-part variation and the comparator is actually capable of spotting the difference between conformant and non conformant parts but not of differentiating between one part and the next as they come off the press.
    What does the comparator compare? Weights, dimensions?
    Lorax
     

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    #139122

    Jonesie
    Participant

    The burr might not be uniform.  Did you try measuring the same location on the part every time, or taking 4 readings and averaging?  The variation might be due to how you are using the tool as much as the tool itself. 

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    #139126

    Jered Horn
    Participant

    Now, now.  I would say this one of those times where % Tolerance can be useful.  The tolerance you would enter into Minitab is the coin thickness multiplied by 0.10.
    Lorax makes a good point about part selection for your study.  You need to make sure all the extremes of your process variation are represented.  I would be surprised if a good optical comparator doesn’t show to be an acceptable gage.
    I thought the “Weight?” post was asking if you’ve considered using coin weight as a way to detect excessive burr.  That may be a possibility…
    Good luck.

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    #139132

    Lugbill
    Participant

    We have tried the same spot and taking multiple readings in order to apply a central limit therom.  Another question that is being debated is when the spec says you are allowed 10% of material thickness, does that include both sides of the tube since you are coining it together? It is acting as one thickness when the hole is pierced. Any opinions? We are allowed .0075″ with only using one side of the wall, using both allows us .015″.

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    #139134

    Haugen
    Participant

    No opinions allowed – ask the customer.  Many times specs are passed on with little thought – could even be a copy-over from a different part/metal, and possibly be wrong.
    Always ask the customer – even if the customer is internal.  It’s all about communication.

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