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Thread: burrs on machined plastic gasket

  1. #1
    Associate Engineer
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    burrs on machined plastic gasket

    What is the best way to callout burrs that are acceptable on parts made with plastic material?

  2. #2
    Senior Engineer Marky's Avatar
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    Hi and welcome to the forum. Is it possible to post a picture of the part? The technical term is "Flash". The way to control flash or burrs is provide a picture of the part with allowable flash/burrs to your QC Dept and to the vendor(s). It gives them a visual to go by.

  3. #3
    Technical Fellow
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    ...or a max acceptable root-thickness and length. Often a circle is used to describe the limits. e.g "Must not exceed .093 radius from square edge." etc.

    Welcome and visit often.

  4. #4
    Lead Engineer RWOLFEJR's Avatar
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    "Acceptable Burrs."
    Yuk...
    Sign of the times I guess. Time is money and if getting rid of a burr requires any extra time I guess it could stay if it doesn't effect form fit or function... butttt stillll.... Yuk!

    How many of you out there have ever been laid open by the razor edges inside of things like computers? That bugs the heck out of me. If I were ever elected King of the World... (humor) I would decree that no burrs are Ever acceptable. Sharp edges allowed when required... but an edge or burr left due to laziness or corner cutting would be a punishable offense.

    One of my first jobs was at a shop where the owner had me deburr every stick of material that came through the door. Guess the habit stuck with me and we don't allow anything to leave our shop without all the edges broken. Ever had an oily stick of heavy cold rolled square bar stock get loose on you and slide through your hands?.... Ouch!! I've even been cut through leather gloves with the stuff.

    (To be said in the voice of Mr. Mackie of South Park... Burrs are bad m-kay...

  5. #5
    Technical Fellow
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    Quote Originally Posted by RWOLFEJR View Post
    "Acceptable Burrs."
    Yuk...
    It's not as bad as it may sound, RW. It makes sense to not reject parts if the burr is acceptable. Quite a few plastics do not leave sharp burrs as the mold deteriorates with wear. Nylon for instance produces more of a bulge than a sharp-burr. From memory and very old memory at that, I seem to recall that Delrin (Acetal) bulges rather than sharp-burrs too. Also a lot of fiber-filled polymers also burr gently.

    But I am with you on burrs in general. I have a small drill press with a permanent deburring cutter for holes in anything. I also have a deburring table that will put a small 45-deg on any sharp edges that can be held in the "V" table. I began my Engineering journey as an Apprentice Toolmaker and "old Frank" my mentor always beat into me, "a job is never complete until it has been deburred."

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