Need Help With Sheet Metal Designing

[JTN]

Improved joint: https://docs.google.com/file/d/0B9fw...it?usp=sharing

[AdamHeard]

Originally Posted by JTN

Improved joint: https://docs.google.com/file/d/0B9fw...it?usp=sharing

That bend will be hard (impossible maybe?) to get.

Rather, make the inside dimension of one rail match the outside dimension of the other rail.

Also, it looks like the two flanges on the left rail coming to a sharp corner with each other is a possible issue. Someone more knowledgeable in sheet working can clarify.

[tim-tim]

Originally Posted by AdamHeard

That bend will be hard (impossible maybe?) to get.

Let me start with I design sheet metal parts on a daily basis. While the top bend that would connect the two flanges is rather difficult, the guys in our shop would say its doable. The caveat to that is I work with extremely skilled artisans that do this for a living. That being said I would never ask them to make this.

That "S" bend in the part is what we would call a joggle. There are special tools and techniques that make this easier. Keeping tolerances can be difficult and may take time to get right.

A more simple solution would be to rivet/bolt a gusset plate across the top two surfaces.

Rather, make the inside dimension of one rail match the outside dimension of the other rail.

This will also work, and most likely be stronger than the above mentioned method. Just be sure to leave room for tangent lines when designing the length of the inside piece. I wouldn't design to the exact distances given by CAD. Give yourself some room.

If you decide to use this method or Adam's method, be sure to give yourself more than a single attachment point between the two pieces. I would use 3 points or so.

Also, it looks like the two flanges on the left rail coming to a sharp corner with each other is a possible issue. Someone more knowledgeable in sheet working can clarify.

Again, this is doable but not preferred. In order to do this you would need dies (or fingers) of the exact length of the flange. This could require cutting tooling. It is also a bad idea from a stress standpoint. A sharp corner (the tangent point of two bends) should be relieved. Most software packages have this as an option in the sheet metal tools. I would put about a 1/16" or so relief radius in this part. It generally also applies to bends that are in the middle of the parts (eg the flange doesn't run the full length of the part).

I would also recommend putting a radius or chamfer of decent size on each corner.

Hope this helps!