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I've tried all kinds of things to get abs to not warp or curl up on the corners and I think I've finally hit upon something that makes a big difference.

After getting the extruder so that it is not hanging off the side of the printer, it lead me to try something with the piece of PVC sheet that was suppose to be the wrap-around for the bottom of the Rostock. I put it around the Onyx plate inside the columns. The belts still move against it a little but there is really little friction. If you are printing something in the center of the bed that is less than 8" in diameter then the effector won't hit it and it does a good job of keeping heat in so that the part cools a little more evenly. I don't think it'll cure all warping but I tried printing a couple of problem pieces on bare glass cleaned with acetone and didn't have any warping.

That's a clever idea.
ABS is a real pain to keep it from curling up. It is amazing how much force can be generated by shrinking plastic... I have had parts actually pull up chunks of glass. Hairspray on plain 1/4 inch Window glass.

Sometimes printing on a raft helps.

Something I wonder about is instead of trying to keep whole print hot is to do the opposite... Cool each layer as it is layed down so the shrink happens right away as you go instead of building up then curling. What I want to try is 3 small tunes blowing right close around the nozzle directed at the bed not nozzle. Use a aquarium air pump.
Probably would need to increase print 10c or so to help new layer stick to previous cooled one.

Anybody have thoughts?

I'm doing some experimenting right now with Nylon 618 and pretty much doing what you are suggesting. I don't know if it is possible to do the same thing with ABS. I'm printing with the heated bed turned off onto Garolite LE with the part fans going at the max setting. If I put my finger on a section that was just printed, it feels just about like room temperature and I'm not seeing any warping. I'm sure a lot of it is due to the Garolite but cooling it down quickly probably helps. The big problem I'm having with Nylon is trying to remove it from the Garolite.

bvandiepenbos wrote:That's a clever idea.
ABS is a real pain to keep it from curling up. It is amazing how much force can be generated by shrinking plastic... I have had parts actually pull up chunks of glass. Hairspray on plain 1/4 inch Window glass.

Sometimes printing on a raft helps.

Something I wonder about is instead of trying to keep whole print hot is to do the opposite... Cool each layer as it is layed down so the shrink happens right away as you go instead of building up then curling. What I want to try is 3 small tunes blowing right close around the nozzle directed at the bed not nozzle. Use a aquarium air pump.
Probably would need to increase print 10c or so to help new layer stick to previous cooled one.

Anybody have thoughts?

IIRC, layer adhesion depends on two factors; the temp of the plastic being extruded and the temp of the layer being extruded onto. If you run tests on this it would be interesting to test for layer adhesion as well, just to see what happens.