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Cams and Wraps

Discussion in 'Using Alibre Design' started by hartlw, Feb 26, 2007.

  1. hartlw

    hartlw Alibre Super User

    Cams and Wraps

    A way, not necessarily THE way, of doing it, or starting it anyhow. Maybe somebody can thicken it.
     

    Attached Files:

  2. lens_cad

    lens_cad Member



    Here is a cam shape that was created as a sheetmetal part. A cylinder was rolled and then unbent to the flat state. A profile sketched on the flat surface (see sketch in position) was used to make an extrude cut through the flat sheet. The part was unbent.

    Additional non sheetmetal features can be added to a part if it is not intended to be an actual sheetmetal part.

    Len
     

    Attached Files:

  3. hartlw

    hartlw Alibre Super User



    Is the cam surface horizontal, so that it can be followed by a horizantal track roller?

    You say unwrap cylinder, sketch profile, and extrude cut. I don't understand last setence: "The part was unbent." Do you mean the part was rebent back into cylindrical shape?

    Was the cylindrical and unbent part the thickness shown?

    It's a fascinating model. Wish I understood it better. Will have to study-up on sheet metal capabilities of Alibre.

    Thanks
     
  4. lens_cad

    lens_cad Member



    Hi,

    I believe that the cam surface would be horizontal. One of the properties of a sheetmetal part is that the edges are always perpendicular to the sheet surfaces.

    I'm sorry, I got my terminology confused. A sheetmetal part can be unbent to a flat state, features added, and then rebent to the formed state.

    The thickness of the material is the same in both the bent and unbent states.

    Len
     
  5. hartlw

    hartlw Alibre Super User



    Len,

    In that case, it looks like you have solved the wrap problem in a very elegant way. Congratulations and thanks.
     
  6. hartlw

    hartlw Alibre Super User



    For anyone who wants to follow up on Len's approach, see section 8.10 of the users guide, "Unbend and Rebend."

    It is stated there:
    "You can unbend then rebend one or more flanges at a time. A feature is added to the feature tree in Design Explorer, allowing you to insert other features, such as a cut, between an unbend and rebend pair."
     
  7. lens_cad

    lens_cad Member



    Thanks, but I can't take the credit for this method. I think it was discussed in the forums in the past.

    However, sheetmetal has some interesting applications for solid modeling beyond the typical part bent from thin sheet steel. For instance a profile can be wrapped around a cylinder and then standard non sheetmetal features such as bosses or fillets added to the part. After the new features are added, the flat pattern may fail but it wouldn't be needed anyway.

    Len
     
  8. hartlw

    hartlw Alibre Super User



    That's it. The problem and solution in a nut shell. I hope others see it. Will try once I get into sheetmetal.

    I am assuming bosses will also be wrapped, and not stick straight out.

    Many Thanks
     
  9. Hi, Would you please point me to where I can find out how to roll a cylinder in sheet metal? I am trying to create an embossing roller die for machining. It looks pretty impossible in Alibre to me at the moment. Is it possible to model an embossing roller die in any other way? This is for cutting out N95 masks using a rolling die by passing over the mask fabric. Something like the attached image.
    thanks
    Sanjeev
     

    Attached Files:

    Last edited: May 16, 2020
  10. DavidJ

    DavidJ Alibre Super User Staff Member

    Use Lofted Flange tool (circle-circle) to create a tube, then Unbend. Add your required detail, re-bend.
     
  11. Thank you David. I will give that a try.
    Best regards
    Sanjeev
     
  12. I can unbend and create detail. But when I re-bend, the details disappear. What am I doing wrong?
     
  13. DavidJ

    DavidJ Alibre Super User Staff Member

    Difficult to say without seeing the file...
     
  14. I have made some progress. But I am doing something wrong. The results are not as expected. Please see the attached file.
    Thanks
     

    Attached Files:

  15. DavidJ

    DavidJ Alibre Super User Staff Member

    Use the SMP cut. Standard part features can cause problems in SMP, and partial thickness cuts are not supported.

    Set sheet thickness to whatever you require the final feature to be.
     
  16. Thanks for the help. I was able to obtain what I wanted.
     

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