Forming tool help

Can someone explain what this error means when I insert a sheetmetal forming
tool?

"The part's thickness may not be compatible with this form tool. The
thickness must be less than the minimum radius of curvature for the form
tool. "

What do I need to change on the forming tool to make it work?

thanks,

 

I don't use the form tools, but I would guess that it's telling you that you
need to increase some forming radius that you have on your tool. It sounds
like you have a small radius that the program can't get the material to flow
around because the thickness of the material is too large relative to the
desired radius and would therefore have to coin it.

WT

 

And it is a way I use to prevent users from using a forming tool on too
large a thickness.

 

Thanks,

That's what it was. The customer was trying to do the impossible...And I
was trying to let him do it.

Jeff

 

Now that's an interesting and seemingly intelligent strategy! What . .
.. do you just include a radius somewhere that won't necessarily impact
the part?

'Sporky'

 

Yes, but I must confess that most of our forming tools are very simple.
Those are designed to be mounted on the same presses we do the bending on.
(forming a hole for ex.)

For the more elaborate (ie. a whole panel), the problem is different as they
are designed for a given part.

 

It is also notable that the forming tools can easily make geometry that
is impossible to attain.

Most apparent are lances (or any form) that are as long as their
opening - they always shorten in real life - and form tools will not
automatically adjust for developed length. Foresight in the form-tool
design process can account for correct development, but this becomes
problematical as the form tool must be adapted for the "as used"
conditions.

Another one comes to mind is on the periphery of a form tool, the
material backside can be dead sharp as if the inner & outer radius were
zero. I have seen this on louvers for example. One can get different
levels of realism depending on the form tool design.

Another big problem is that the form tool cannot (usually) in any way
have a disparity between the punch & die side of a feature - i.e.
cannot account for size differences in shear/break. Generally this is
not a huge problem if one dimensions the die or punch size exclusively
(not using both sides to define definitions). Related to this is the
inability for a form tool to model things with different punch / die
sizes. Take a simple semi-perf for example. Anyone worth their salt
(my opinion - dissenters received) would not size a punch for a
semi-perf _smaller_ than the die opening as it creates a shear (weak
semi-perf). Common practice is to size the punch _bigger_ than the the
die to create more of an extrusion and create less of a shear line
(remember it does not enter and does not need to be smaller). Form
tools cannot deal with this very well.

Form tool detail all depends on what one needs (part designer or tool
designer), so there is usually a way to create the geometry needed in
either case. What a part designer and a tool designer deem passable is
often different.

Later,

SMA