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Sheet Metal - Dimpling

Discussion in 'Using Alibre Design' started by PaulProe, Mar 30, 2021.

  1. PaulProe

    PaulProe Senior Member

    I am trying to draw a fan blade that incorporates dimpling for rigidity. With the issues I am having, I am unsure if it is my limited skills on the use of Alibre or is it that Alibre Sheet Metal features are rudimentary at best.

    I am able to make simple dimples. I've been able to make some shaped dimples but it very quickly goes south as I try to replicate these shapes. I've looked at the documentation and am learn absolutely nothing. Is there any documentation or details on how to use this tool?

    I've attached a picture of the part. It is 9" in diameter, has 5 blades. I really don't care about the pitch in the blades (although, that would be nice), I am trying to replicate the star-shaped dimple in the center.

    Thanks for any suggestions or help

    Paul
     

    Attached Files:

  2. wsimonton

    wsimonton Senior Member

    Good Question. I have had a similar issue and resorted the to doing the hard way. See attached. I would still like to learn how to manipulate the dimple feature.
     

    Attached Files:

  3. HaroldL

    HaroldL Alibre Super User

    @PaulProe There has been several enhancements requested for Alibre Sheet Metal. Some have been added, kind of. Others are still being waited for. What you need for the emboss on the fan blade is likely best created by using the Part Modeling tools and creating a Boolean feature. That means you'll need to create a part in the shape of the emboss and then Boolean that to the fan blade.

    @wsimonton , I'd suggest using a linear pattern inside your Boolean, that way you won't end up with such a long list in the Design Explorer.

    I have the v23 Beta installed now so I cannot provide an example.
     
  4. sz0k30

    sz0k30 Senior Member

    The "Sheet metal feature" is basically for bending, not for forming.
     
  5. idslk

    idslk Alibre Super User

    upload_2021-3-30_19-12-29.png

    Regards
    Stefan
     
  6. PaulProe

    PaulProe Senior Member

    Stefan
    that is exactly what I've been trying to do. How did you accomplish it. Mind sharing your file

    Paul
     
  7. HaroldL

    HaroldL Alibre Super User

    Paul, after taking a closer look at your fan blade image it does appear that it can be modeled in Sheet Metal as Stefan shows.
    Once you have the dimple feature all that is needed is some Sketched Bends to give the blades their final shape. I thought the blades were bent thru the area of the dimple that's why I thought you'd need to create it as a Boolean.
     
  8. PaulProe

    PaulProe Senior Member

    I have played more with the dimpling tool and finally was able to get to Stefan's image. But it took a LOT of trial and error. The help screen is absolutely worthless.

    I recognize that technical writing is difficult and tedious. But it really needs to move up the priority list with future versions.

    Paul
     
  9. HaroldL

    HaroldL Alibre Super User

    Paul, Hopefully the Help is being rewritten for v23 so that it starts to make more sense for some of the more involved features.

    The one thing that is a bit confusing when you first start using the Dimple tool is that the dimple protrudes opposite the surface you put the sketch on. That's caught me off guard a few times. Think of the sketch as the punch and the dimple is pushed thru the sheet metal to the far surface. Only one sketch is allowed per dimple feature. So, in the case of your fan blade, and as Stefan shows in his model, there are two dimples that protrude in opposite directions. The first dimple is the outer shape of the dimple star shape. The second dimple would push the center area of back down so its surface is aligned with the base tab.
     
  10. PaulProe

    PaulProe Senior Member

    Harold
    one of the issues I was facing - if the parameters caused Alibre to hiccup, it would extrude in the opposite direction or the corner radii would stack on top the extrusion. Really wierd behavior. I suspect the coding is not 100% on this feature. But I really don't know enough of it so say what's right and what's wrong.

    I learned early on about the need for two dimples. Still playing with it, I'll get there yet

    Paul
     
  11. HaroldL

    HaroldL Alibre Super User

    I gave it a try in v23 Beta and got some odd results myself. After the first attempt failed ( it actually created some sort of extrusion as seen in the image below ) I tried a second on the opposite side and that one failed too. After looking at the file a second time I found that the sketch had taken on a shape of its own choosing. After rebuilding the sketch the dimple worked as expected but I have no idea why AD gave the results it did. And I did report this to the Beta support.

    I suggest sending the file to support just to get their expert eyes on it.

    Here's an image of my first results. Are they anything like what you experienced?
    Odd Dimple Result.png
     
  12. PaulProe

    PaulProe Senior Member

    Harold
    Mine did something very similar except some of the corner blends were between the outer part of the dimple and the base piece. Almost looked like a crown on the base piece.

    I am doing it with Alibre22 so there must be something wrong in the base code that is carrying over to the new version. There must be something in the coding that if it occurs, the direction factor is reversed. My experimentation shows it might be related to the length of the legs of the stars. When I shortened them using the same outer radius, the problem resolves itself.

    I am not on the beta but will post a link over there to this.

    Paul
     
  13. HaroldL

    HaroldL Alibre Super User

    Looking at the list of things added and bugs fixed in v23 Beta, I don't think anything was done that would affect the sheet metal tools, That said, and that both versions seemed to have the same issue, send the file to support for examination, maybe they can figure out what is causing the issue with the part.
     
  14. idslk

    idslk Alibre Super User

    Not my best... (but wouldn't do those with sheet metal...), also i used some random dimensions...

    "upper side"
    upload_2021-4-2_22-44-31.png

    "lower side"
    upload_2021-4-2_22-46-13.png

    bend:
    upload_2021-4-2_22-29-28.png

    flattend
    upload_2021-4-2_22-30-47.png

    I haven't deeply tried to find a way to pattern the "sheet metal cuts" and so on...instead i used a 3D extrude cut and some other lazy sketches...
    But you asked for the file ;-)

    Regards
    Stefan
     

    Attached Files:

    Eddy So likes this.

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