SHEET METAL FAIL

michael_mcewen

I’m trying to create a part to then convert into a single, flattened sheet metal pattern:  a polygon with vertical, triangular ears, and 3 bent tabs on each of the long open sides. I selected thicken since I couldn’t convert or extrude.

Try as I might, I cannot get the sheet metal tool to include my 6 tabs. The side triangles form bends to the main polygon, and show up in the flat pattern as a single part, but the 6 tabs remain as separate parts.

I've watched all the tutorials / videos. Before I used the sheet metal tool, I extruded all the parts, minimally, because otherwise the sheet metal tool would not allow me to select edges to bend.  Could this be part of the problem?

I then tried to create the tabs using the flange tool, and then extrude / remove to trim back, but I was not successful in creating the tabs, as shown.  

Can anyone help me out here?  I'm 6 hours in and going nowhere . . . here's a link to my file: https://cad.onshape.com/documents/59eb2b7a41c24370a6b7a430/w/22319e6983cde957321a771b/e/bd684f6922cd179a4c0059e8

Thanks!

john_mcclary

You should double check your sketches, they are blue, and some of the edges are not parallel to the sheetmetal model edge.
Also the lower radius is messing with the relief cut. 

by explicitly defining the position of the flange, you can see it is off by a little bit.
Below was done using @mbartlett21's Shaped flange feature, which lets you sketch your profile, then attach it to an existing piece of sheetmetal. It may come in handy for you https://cad.onshape.com/documents/602655eff016f183fc184978/v/774be7b6cad2fe5b9279e2b3/e/19d0707305639254781cb5d0


Otherwise the same thing could be done by adding some relief cuts early.



add your flange


Then worry about the fillets at the end


Then you can use a symmetrical linear pattern and get the other two profiles without sketching them


Here is the document I worked from if you want to look into it:
https://cad.onshape.com/documents/5ad96f957b416776130fcf7b/w/fe798331b2e06e33017cb9a7/e/45e26938aed1a3e120157eb7

philip_thomas

Sheet Metal WIN!

michael_mcewen

Thanks John, I went over my sketches and made sure all were lines black; I guess I was being a little sloppy!  I couldn't figure out how to use  @mbartlett21's Shaped flange feature. Is that feature script?  I haven't learned what that is or how to use yet.

I did try your suggestion of cutting the relief cuts first, which worked well for me.  I ended up using the flange tool to make the 6 small flanges as well as the side, triangular pieces, after thickening the base polygon with the sheet metal tool.

As for the sheet metal tool, it seems as though it's not possible to either create a flattened shape with sides that are not 90º or with sides that are not rectangular.  Not sure which. But, I was able to make thepiece with flanges . . .

https://cad.onshape.com/documents/59eb2b7a41c24370a6b7a430/w/22319e6983cde957321a771b/e/3d61ba56bdd0162093cc4fd0

Thanks again John, and Philip!

Jake_Rosenfeld

@michael_mcewen

To use the custom feature above, you can click on the provided link; at the top of the page that loads you should see a button that says "+ custom features".  If you press that button, a tool will be added at the very end of your toolbar so that in your own part studio, you can use the custom feature like any other feature in Onshape! No need to learn any coding or new concepts.

michael_mcewen

Hey Jake,  Oh, OK, not so hard as it looks!  I will do it.  Thanks for explaining!

john_mcclary

Yea, like Jake said, just click the


then copy the link I posted earlier and paste it here


then click the shaped flange feature

then it should appear on your custom feature list

To use his feature just select the edge of the sheetmetal part the face will attach, then select a face to add as a flange.
You can use a sketch instead of a face too, so no need to extrude your "fake" tab first.

Keep note, you will need to be thinking about how the metal will deform when adding flanges. Most of the time the relief cuts will appear automatically, but whenever you have a non-perpendicular edge you will need to add your relief manually, or stop just short of your bend radius.
example: 

john_mcclary

guess I shoulda waited a few more seconds, before posting this long message lol

michael_mcewen

Very cool John.  This is super useful. Thanks for taking the time.

michael_mcewen

This forum is great.

john_mcclary

michael_mcewen said:

This forum is great.

We try 

MBartlett21

@michael_mcewen
Glad to know the feature is useful!

michael_mcewen

Yes, thanks m@mbartlett21 !!