HOW CAN I MAKE A SHEET METAL FLAT PATTERN FOR A TRUNCATED CONE, TO MAKE A HOPPER?

shawn_crocker · March 2021

@mauricio_hernandez
I'm hoping onshape will automatically convert your words "how can I make" to "we should be able to make" so that this gets properly absorbed as an improvement request. I was surprised that sheet metal cones are not possible out of the box. Ended up getting curious and found some stuff that lets it happen but is an indirect sort of way. I imagine it would still function well when sent to be MFG. Check this document where I have tested it out and left a little screen recording of how I implemented the custom feature and cleaned up the resultant geometry. sheet metal cone example | Part Studio 1 (onshape.com)

kent_henderson · March 2021

It would be so nice to be able to do this easily. It can still be done but it's a lot more work than SW or Inventor. Onshape won't consider conical shapes as sheet metal. So you must do this faceted, like if you were going to bump form this in a press brake. Inside your circle sketches, inscribe a polygon. Make sure each polygon has the same number of facets an that the facets are oriented in a logical way, i.e.not twisted top to bottom. Now you can either loft a solid between the sketches and convert to sheet metal. Or, loft faces and turn each facet fact into sheet metal. You'll need to indicate in the SM feature which facets are formed. The flat pattern will be perfect if you have your K factor right.

Image: https://us.v-cdn.net/5022071/uploads/editor/as/3torv7s7kwj5.png

kent_henderson · March 2021

I just looked at how you did that. And that's trippy cool. Triangulation is old school, but it still works. Nice work for thinking outside the box. I will agree with you that we shouldn't have to. I use the faceted SM cone shown above all the time. The flat patters work out fine whether rolling or bump forming. We use both methods depending on material, thickness, taper, sized, etc. These faceted cones do produce very accurate flat patterns.