Any ideas on flattening a surface with compound curves?

I have a part with compound curvature, that I need to flatten to get a
sheet metal flat pattern. This part also has holes that have their
location defined in the final curvy part, but also need to be in the
flat pattern. There are no flat faces. Any ideas?

 

Whatever you do, don't let a CAD system do this for you. It WILL be
wrong. (Pro/E could do this somewhat, but it was ALWAYS wrong.)

All of the stamping die firms I worked with had special software for
developing flats of odd shapes. None of them would accept a flat
pattern from outside (or customer) except for quoting purposes.

Flattening regular sheet metal bends is not difficult (for a computer).
It is mostly simple algebra. Flattening compound curvature is far
more difficult. It is a close cousin to FEA.

 

Unless it can be flattened by the SolidWorks sheetmetal function you
need to look at a SolidWorks partner product like:-
www.blankworks.com

John Layne
www.solidengineering.co.nz

 

Any ideas?

Not without knowing the Guassian or mean curvature and what you expect of the
flat profile.

 

Curvature on the part is approx 84" radius in the "x" direction (top
view), and approx 44" in the "y" direction, on a part approx 12" long.
Basically a potato chip. What do I expect from the flat pattern? Not
much really. Maybe to fetch me a drink, bring in the morning paper,
something like that. No, really, the flat pattern would be put in a
form die to create the final part.

 

The part size, in relationship to the radius of curvature, is such that you
might get away doing the following:

-Create 2 projected curves through the center of your part, one parallel to
x, one to y so that you can measure their length.
-On a suitable plane for a projection, open a sketch and convert the
perimeter edges.
-measure your distances in x and y at the same points your curve goes
through.
-create a flat solid from the converted edges
-do a non-uniform scaling of the part ( ie for x, curve length/projected
length... probably in the neighborhood of 1.05 )

That should get you pretty darn close, probably as close as most forming
software.

 

Check with blankworks. You should be able to get a 14 day working demo
to try out. We had an airfoil form that needed to be flattened out and
blankworks was the only one that worked for us.