Cutout patterns for bent (curved, not angled) sheets of plywood or aluminum?

adam_derstine

Are there tools in OnShape for 'unbending' ? I want to generate patterns to cut out for a boat design, but I don't know how the curves I've generated could be flattened or even if they could be flattened.

Here's a bit of example geometery.

Sheet metal tools in OnShape don't really apply - that's for tabs and more or less right angle bends... this is much different. I'm sure somebody has dealt with this before but I'm stumped.

S1mon

It seems like your document is not public.

adam_derstine

Sorry - I'm probably missing something but I'm on a free plan so I think all my documents are public - do you know what setting I need to change?

I updated the name and recopied the link out...
https://cad.onshape.com/documents/14bf4c63cbd1bee19fa59e4c/w/a74404a581ccd6a2bdd8c64a/e/a8ea2fe68fa4f6cc127203ed?renderMode=0&uiState=640dec967628f06b685645fc

MichaelPascoe

@adam_derstine, the sheet metal tools would work for this. However, you will need to tweak your model to only have extrudable and flat faces as the current sheet metal tools don't allow lofted faces that aren't bent only one direction.

Once you turn it into sheet metal, you can refresh your page, and you will see the sheet metal flat panel over to the right of the screen.

A workflow similar to this would allow you to use sheet metal:
https://cad.onshape.com/documents/8298ee8c9687a4cdea8aea06/w/a88441bf5a3fe29f2d078edc/e/e187b0a45e61befdab87eddd?renderMode=0&uiState=640e7854689e8c3cae8deead

S1mon

I don't know what happened when I tried to open the public link previously. Perhaps because I was on my iPad logged into an enterprise account? Anyway... it works for me now.

Onshape can handle flattening things that are curved in 2D only. They don't have to be arcs, they can be splines, but they need to be 2D. With some small tweaks to your shape, I think it's possible. In general, Onshape is not great at flattening complex shapes. They've announced updates which will handle flattening lofted sheet metal (think the transition from a round duct to a rectangular one), but it's not clear yet it that will work with any developable surface.

@MichaelPascoe I had thought that the curves needed to be arcs, but recently I tested with splines and it worked. I’m not sure when that changed. 

For anything which requires some forming, stretching or splitting into gussets, you'll need to look to other tools.

MichaelPascoe

@S1mon, perhaps it can be a curve as long as it is only bent one direction. So anything that is extruded, can be turned into a sheet metal part. But not anything that is lofted can be, yet.

adam_derstine

MichaelPascoe said:

@S1mon, perhaps it can be a curve as long as it is only bent one direction. So anything that is extruded, can be turned into a sheet metal part. But not anything that is lofted can be, yet.

Thanks! I'll check it out ... I haven't really learned any sheet metal yet because i thought it didn't apply, but now I will!

adam_derstine

So this works, basically - here's my little sandbox project where i'm trying to do it.

I have two surfaces and I'm using them to cut each other. I can make each one into a sheet metal object, but I can't make both of them part of one sheet metal object. I've tried a couple ways of doing the conversion, different highlights, etc... is there something I'm doing wrong there or should I expect each one to be its own separate sheet metal entity?