Convert a partial cylinder into a sheet metal model ?

franz_balleis127

Hello, yesterday evening we had a little discussion how we can laser parts of a metal dish.

My first approach was to convert this into a sheet metal model, but unfortunately I couldn't.

I have deposited a simple bowl on my onshape page. 

Does anyone have a tip for me on how I can solve such a case.

matthew_stacy

@franz_balleis127 this part may be simple to model in CAD software, but somewhat more complex to fabricate in the shop.  How do you intend to proceed after the flat pattern has been laser cut?  The difficulty is that forming this part will require non-uniform plastic deformation.  "Sheet metal design" in the context of CAD software is premised on the assumption of constant sheet thickness.  The shape that you have designed cannot be "developed" into a flat pattern without violating that premise.  There are software packages (E.G. Exactflat) that can flatten complex curved surfaces, but Onshape will not do this.

As-drawn this part could potentially be 3d printed or cast.  A skilled tinsmith could perhaps persuade a flat sheet of metal into this shape with an abundance of patience.  With some design modifications and expensive tooling this part could probably be made with stamping operation.

A more viable approach is to make the cone and floor separately, but you will have to figure out how to join the seam where they meet.  The cone can be APPROXIMATED as a series of bends that Onshape can convert to sheet metal to generate the flat pattern:  https://cad.onshape.com/documents/be70e4a2e47a30c383311b6e/w/c216228e46bc41de1fc01906/e/d6f0871b7627180dbfd035a7

Increasing the number of bends (#n) improves the approximation but becomes more onerous to fabricate.