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Sheetmetal "Unbend" issue

Discussion in 'General Discussion' started by Kevin931, Aug 21, 2020.

  1. Kevin931

    Kevin931 Member

    Hey guys. I appreciate all the help with all my problems I encounter! Got one more to run by everyone, first time I've run into this issue. I'm trying to use the "Flat Pattern" button on a sheetmetal part and it's now giving me an error that I can't figure out. Here's the message I receive in a pop up window when I try.....

    SMUNBEND_INVALID_BODY_FOR_UNBEND: Invalid body supplied for unbend.

    Anybody have any experience with this and what I should be looking for to correct? Thanks!
  2. DavidJ

    DavidJ Alibre Super User Staff Member

    It might help if you upload the part...
  3. Kevin931

    Kevin931 Member

    Here's the part in question. I was working just fine for me to begin with, however I sent it out for production and they emailed me back saying they couldn't get the file to unbend (they use solidworks). I went back to the drawing to try and diagnose and now it's giving me the error and won't unbend in Alibre either.

    Attached Files:

  4. DavidJ

    DavidJ Alibre Super User Staff Member

    If you suppress cut 8 it unbends fine.

    Try unbending - then do your cut - then re-bend.
    Last edited: Aug 21, 2020
  5. Kevin931

    Kevin931 Member

    I'll also note that I didn't add the last "cut" sketch to the part until after they said they were having issues with it on their end. I thought maybe that corner was causing complications.
  6. HaroldL

    HaroldL Alibre Super User

    Rather than trying to sketch around the odd shape of the notch, just use a circle to define the shape of the "bend relief" you are adding. By carefully placing the sketch you can relieve both bends and the resulting bend relief can be filled in with a weld bead if needed.

    Round Cut Sketch.png

    Round Cut Flat.png

    Round Cut Result.png

    I also noted that you are using Inch Fractions for your part. In my experience it is best to use decimal inches for sheet metal. You have much tighter control on dimensional sizes. IF the shop uses fractions for production well...then you need to give them what they want.

    In this case I changed the dimensions to decimal and located the circle to be centered on the LH bend region, coincident to the end of the tangent line and just large enough to cut both bend regions.

    Attached Files:

  7. Kevin931

    Kevin931 Member

    Thanks for the help. I was able to tweak a few things on my drawing and that made things work out for my supplier in Solid Works so all is well now.

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