Pretty round sheet metal part

[Morglisn]

Hello again, guys. Yes, I'm still working with that thick, nasty insulation that I can't seem to draw properly. I'll try to describe both the flat pattern and the final product. For the flat pattern, let's start with a basic rectangle. Then, take two triangular cuts out of each side. What we're looking to model is a cover for an L-shaped elbow. The middle of our rectangle will cover the outer side of the elbow, and the edges (where we've cut the triangles) will join together at the elbow throat. The triangular cuts will allow us to meet the material at the throat, without any visible overlap.

I've tried starting this both folded and unfolded, and can't seem to get anything going.

I appreciate any help, as always.

 

[TheTick]

The main problem is geometry, not software. A pipe elbow is a compound bend, a curved surface going around a corner. SW sheetmetal (and most other sheetmetal packages) is the inability to unfold compound (non-Gaussian) bends. Trying to unfold a globe into a flat map is a classic example of a compound bend problem.

One approach might be to model a narrow, "flattenable" strip along the outside meridian of the elbow, and add flanges to the sides. You still won't be able to unfold a flange built along the curved portion of this meridian strip". Gravity is a harsh mistress.

 

[Troberts]

Morglisn:
I believe you can solve the problem by using a Miter Flange. The "Getting Started" book has a discussion on pages 19-2 and 19-3. First you sketch a 90 degree angle, do the Base Flange thing. Then the tricky bit, select the EDGE you want the flange to be on, the inside one. And then click on the sketch icon. If you have done everything right you will get a plane normal to the edge selected. Sketch a line the length of the flange, and select miter flange. You should get a flange down one side of the 90 degeree angle, select the propagate icon that appears and you will get the continuation of the flange with a miter. You can then mirror the part to get the other half of the part. If you unfold it you will get the square of material with 2 notches you were talking about. I don't think the result is exactly acurate because when you look at the folded part in thick material there are large notches in the material at the corners.

Hope it helps.