guynoir wrote:
http://www.americanmachinetools.com/...e_strength.htm

Ah, thank you!

More important considerations are bend radius and springback. ...

Thanks again for the very helpful info.

Most press brakes come with sharp upper dies and 90° "vee" lower
dies. Neither work very well with hardened aluminum alloy. For
aluminum, you need a "U" channel in the bottom die, and a
radiused upper die.

That's quite interesting. Would the geometry of this bend be such that
the (presumably rounded) edges of the U channel would "wipe" or slide
against the aluminum as it is pressed in between them by the upper die?
If so, does this validate the approach of this homebuilder --

http://www3.sympatico.ca/murray.j/tools.htm

His idea is that the hinge line of his brake need not pass directly
through the exact meeting point of the apron and bed surfaces -- the
metal will slide across the apron to compensate. Thus he is able to use
a series of hinges to support the apron all along its length, and can
therefore get away with a less-stiff apron.

If this builder's idea is correct -- and validated by the geometry and
usage of press brake dies -- why are not more industrial bending brakes
built to take advantage of this? Or, what am I missing?

Thanks a huge lot. Peace,

Ihab

--
Ihab A.B. Awad
email: firstname dot lastname at gmail dot com
Palo Alto, CA, USA