help with sheet metal problem

sw2006sp5.1 I've used sheetmetal very little and I'm kind of lost on this part. I'm trying to make a sheet metal part that looks like this sample surface.
http://briefcase.yahoo.com/bc/ snipped-for-privacy@sbcglobal.net/lst?.dir=/Docs&.src¼&.view It would be made on a press brake so the inside radius on the bends should all be .125" and the material would be 0.1". I tried to do this as a sheet metal loft, but I couldn't seem to control how the different line segments connected between the two sketches, so I never got the triangular surface. The following statement was in the help system, "If the loft preview shows an undesirable loft, re-select or reorder the sketches to connect different points on the profiles." This seemed like maybe a relevant concept, but they stopped short of actually revealing how it's done. If it is necessary to fudge by cutting a hole (rip, relief,etc) at the sharp point of the triangle, that would be fine because I'm mostly concerned with deriving the periphery of the flat pattern. In real life this area is distorted some anyway. I'm hoping I can put a large blend/fillet on the edge between Surf2 and Surf3, so there isn't a visible edge there. Is a loft the best approach, or do you think shelling out a solid would work better? Any ideas would be appreciated. Thanks, Bill
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
wrote:

http://briefcase.yahoo.com/bc/ snipped-for-privacy@sbcglobal.net/lst?.dir=/Docs&.src¼&.view=

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try it now. I'm surprised though, that Brian could open it before. Hard to figure.
Thanks, Bill

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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.
--
Brian Hokanson
Starting Line Products
  Click to see the full signature.
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
yes, you need some relief. ;)
https://home.comcast.net/~kennethbarrentine/TestDart3.zip
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
<snip>

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.
<snip>
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
Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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

Add pictures here
✖
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.