Sheet metal question

[prooney]

I've got a sheet metal part that has some cut outs that are rather close to bend lines and when we go to bend them the cut out areas flare out. Is there anyway to leave material inside the cut out in my model so that they can open the cut out after forming? I've attached a picture of what my finished part needs to look like. The large cut out area is where I'm needing a "stitched" outline of the finished cut out.

I'm thinking I may have to do it with a configuration but not sure. I'm using SW 2012. Thanks.

 

[Eltron]

This sounds like a manufacturing issue, not a modeling issue. Would putting a note on your drawing suffice?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[prooney]

Eltron thanks for the reply. Yes I could put a note on the drawing to call that out which I will probably end up doing anyways but I'm using the dxf file from the flat pattern for our laser to cut the part out. I was trying to eliminate me having to "massage" the dxf file. Hoping that SW had a feature for this or that this could be done inside the part file.

 

[GRF]

You could make a seperate variation for the laser cut and one for the final product. In the laser cut variation you can suppress the features that cause the problem for the bending process.

 

[drawoh]

prooney,

I systematically set up my sheet metal models as assemblies, so that I can add thread inserts and gussets and stuff like that. In this case, you leave the hole out of your sheet metal model, and you add it at the assembly level. Presumably, someone will machine it.

Subsequent machining of a sheet metal part means you add a manufacturing process, at significantly higher cost. I would try very hard to find some other solution to your problem.

Can you make box bigger?

If the problem with the cut-out is on one edge, can that edge wrap around the bend?

Can you use thinner material?

Can you use softer material?

--
JHG

 

[prooney]

Drawoh,

There is no machining performed on this piece. The shop will use a hand plasma to cut out the stitches to remove the remaining material. I'm stuck with the size of the box as it is. The material is 12ga A36 which I can't deviate from either.

 

[DiegoLGraves]

Proony, if this is being fabricated in-house you may be stuck with the tooling available. Based on the pdf (no dimensions other than 12ga A36)if it is sent to a job shop it can be formed complete using rolla-v press brake tooling or on a folding machine. You can also suggest the brake department start the bend (60° maybe) with a narrow v-die, then switch to a wider v-die to finish forming to 90°. If you have a laser it can also be fixtured to cut the windows after forming. Back to the modelling question, use a secondary configuration for the final part shape; put the extra material in the first configuration so it's included in the flat pattern, and is shown as formed for the forming team.

2 cents worth, Diego

 

[hititfaster]

I think I'd make it in two parts and weld them together. You could bend the left, top and right faces (as they appear in the pdf) as one part then weld the front face on.

 

[MadMango]

You can create a "stitched outline", but it can't be just a line. You'd have to create rectangles, with the minimum width like .005" or so. I've done this in the past with good results with similar thicknesses. As for the production issue, it seems like your cutout edges are close to 2.5T+R from the bent edge, so not sure why you are having the issue. Can you use a smaller bend radius? If so, the forming tool might support the material better. The shop may be able to also insert the formed part into a press and push the raised edges back into place.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?

 

[prooney]

MadMango,

At what point would I added the "stitched" section in SolidWorks that would be cut out after forming?

 

[MadMango]

The stitched area should be in your model so it will be present in the flat pattern for cutting and forming. The full cut-out should be there after it is formed. At least that is the way I see things, I consider it a giant knock-out.

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read faq731-376 to make the best use of these Forums?