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Making press die.

Posted: Wed Jan 09, 2013 10:12 pm
by mcostello
I frequent the other boards on this BBs, first post in this forum. I am making a die and punch to bend some 14 gauge Aluminum to a 90° corner. Piece is 14" wide. What angle do I make the punch?

Re: Making press die.

Posted: Thu Jan 10, 2013 1:44 am
by Harold_V
I'm not a die man, so I can't respond with any degree of reliability. Thought I would mention, however, that the material you choose to use would most likely make a difference, maybe even a big difference. Aluminum, dead soft (condition 0) would most likely respond way different from aluminum in a T6 condition, for example.

Grain makes a difference in some alloys, too. Make sure your bends are in keeping with good practice, to avoid cracking.


Re: Making press die.

Posted: Thu Jan 10, 2013 7:25 am
by GlennW
One method is to use a fairly universal punch and die like the ones shown and control the bend radius with the nose radius of the punch, and the bend angle with the depth the punch is pressed into the die.
Punch.JPG (17.58 KiB) Viewed 7331 times
Die.JPG (26.79 KiB) Viewed 7331 times
A full form punch and die is another method, but would need quite a bit of trial and error to get the exact angle needed on the punch and die to produce a 90 degree bend in the alloy, temper, length, and gauge metal needing bending. That type would make full contact on all four flat surfaces of the punch and die.

The easiest is just to make a punch die similar to the one above as far as angle, make the nose radius to match the bend radius you need, and press it into thick die rubber or polyurethane, controlling the bend angle by the depth of press. It will also leave no marks on the metal when bending and have a near perfect bend radius. Back in the early nineties McMaster Carr sold a 2" square polyurethane bar with about a 3/4" hole though it length wise for use as a lower press brake die for light gauge metal. It was the slickest thing I had ever used as it was totally universal. You could press radius, knife, or form dies into it with perfect results and no marring.

You can also make the nose radius of the punch fairly small whan pressing into rubber and simply shack 1/32" sheet on the punch to increase the radius when needed rather than having to make different punch dies.

Re: Making press die.

Posted: Thu Jan 10, 2013 10:07 pm
by mcostello
Thanks for the advice, Mark