help with sheet metal problem

Bill,

Your Yahoo Briefcase is giving a message that you have not shared your folder, so we can't see your file.

Regards,

Anna Wood

I'm no sheet metal expert. Basically this is what I see. The triangular surface technically can't be made by bends alone. By bending those two bends you are actually forming the material ( stretch along the long edge of the triangle and compression along the edge between surfaces 2 and 3 ). Solidworks does not yet understand forming, only bends.

Here is a way to get around the limitations. Take surfaces 1-3 and knit them ( exclude the triangular surface ). Radius the edge between surafes 2 and 3. Thicken the surface. Insert-sheet metal-bends. This converts it into sheet metal that can be flattened. There is a warning given in the bends, but its not significant to the outcome. This will give you a starting point for your periphery.

To take into account for the stretch/compression thats occuring. Look at the flat condition, with the triangle's wedge on your left. The lower left corner of the part, and the lower left corner of the wedge won't be in the correct location. You'll have to form a part, measure it, then adjust them to bring your part to within tolerance.

The alternative is finding someone with forming software and have them do your flat pattern.

Try it now. I'm surprised though, that Brian could open it before. Hard to figure.

Thanks, Bill

It appears that sbcglobal is even more hosed than usual this evening. Half the times I've tried, I can't even access that folder myself.

I think I know a partial solution already, i.e. the need for the addition of a rip to avoid distortion/forming which would have occurred, as Brian said. I still don't know what's the best strategy for the design, but as I think more about it, I can probably do everything with sketched bends instead of lofts.

Thanks, Bill

yes, you need some relief. ;)

The bend that makes the lower edge of the triangle is actually being done with the press ram tilted, and they of course get some distortion (tolerable for what they're doing) in the spot where you put the relief cut. They can't do a regular bend because the material continues further than is shown on the sample. With ram tilt (there may be better lingo for this), the triangle face is twisted somewhat, and I'm assuming that swx can't resolve something like that as sheetmetal. Do you think the design I've shown is about the only way to approximate that type of bend, and would it produce a reasonably accurate flat pattern? I realize that some relief cuts, etc will need to be dealt with manually for programming the cutter. I hope these questions aren't too dumb, but this is one of my first projects involving sheet metal.

Thanks, Bill

Correct

you're close. you could tweak the extension (surf3) a bit to remove that blend line (just a visual thing).

also, you could scale (or not) the part down somewhat and do some setup parts. this should give some idea as to the corrections you will need to apply for final flat. this is almost a must do.

what you're doing here is very similar to a cross brake. mild "x" shape bends across a panel to add stiffness. sw can't do this either.

you couldn't have picked a better part to start with! :D

I'll be able to tweak the flat part, I just didn't want to be embarrassly far off the mark the first time through. I guess I'm trying to limit second guessing of my modeling technique, later on. :~) Thanks a lot, Bill