We do a job every so often where we mill .19" thick 5052 aluminum plates
about 34" by 26". We take about 3/16" off the edge all the way around,
notch a couple of corners, and put miscellaneous holes in the interior. The
first time we ran some they curled up 3/16 to 1/4" when we released the
vacuum plate and took them out of the mill so we found a company with a
plate straightener and after they ran the plates through they stayed flat
after we milled them. They were flat to start with but the extra stress
relieving did the trick. Unfortunately, after about 9-10 years of running
our plates they realized that their machine was only rated for 0.090" thick
mild steel and they were seriously abusing it with our plates and now they
won't run them, sigh :-(. I have called about a dozen shops in the
Baltimore/DC area and found lots of shops with three roll rollers and press
brakes who claim "yeah, we can straighten anything", but no one with a real
straighener (pair of entry pinch rollers, a series of say two over three or
three over four rollers that bend the plate back and forth, and a pair of
exit rollers). Our plates are plenty flat to start with, it is the extra
stress relieving that we need. Does anyone know of a shop anywhere close to
us that can do this for us? Does anyone know of any other way we can keep
the plates from curling up after machining?

-----
Regards,
Carl Ijames

On Fri, 25 Jun 2010 22:10:12 -0400, "Carl Ijames" wrote:

We do a job every so often where we mill .19" thick 5052 aluminum plates
about 34" by 26". We take about 3/16" off the edge all the way around,
notch a couple of corners, and put miscellaneous holes in the interior. The
first time we ran some they curled up 3/16 to 1/4" when we released the
vacuum plate and took them out of the mill so we found a company with a
plate straightener and after they ran the plates through they stayed flat
after we milled them. They were flat to start with but the extra stress
relieving did the trick. Unfortunately, after about 9-10 years of running
our plates they realized that their machine was only rated for 0.090" thick
mild steel and they were seriously abusing it with our plates and now they
won't run them, sigh :-(. I have called about a dozen shops in the
Baltimore/DC area and found lots of shops with three roll rollers and press
brakes who claim "yeah, we can straighten anything", but no one with a real
straighener (pair of entry pinch rollers, a series of say two over three or
three over four rollers that bend the plate back and forth, and a pair of
exit rollers). Our plates are plenty flat to start with, it is the extra
stress relieving that we need. Does anyone know of a shop anywhere close to
us that can do this for us? Does anyone know of any other way we can keep
the plates from curling up after machining?

-----
Regards,
Carl Ijames


That's a tough one, since it's not heat treatable. You might be able
to anneal it with heat, but you'd need something to re-work harden it.

Sounds like a heavier duty plate straightener is needed. Good luck.

Pete Keillor