ABS is fine right up until it isn't. The first centimetre prints beautifully, you wander off feeling clever, and you come back to a part with one corner peeled off the bed like a Post-it note, or worse, a tall part split clean along a layer line halfway up. Both are the same problem wearing different hats: the plastic is shrinking as it cools, and the bottom of the part has cooled while the top is still hot, so the part fights itself until something gives.
I spent far too long treating this as a slicer problem. More brim. Hotter bed. A raft. Glue stick, hairspray, the magic juice of the week off a forum. All of it helped a little, none of it fixed the tall parts, because the actual issue is the air around the print, not the surface under it. The bed can be at 100°C all it likes; if the room is at 18°C then the part is sitting in a thermal gradient and the upper layers contract against the lower ones with real force.
The fix everyone tells you about, and they are right, is an enclosure. Keep the ambient air around the print warm and steady so the whole part cools slowly and together. I'd resisted it because "build an enclosure" sounded like a project, and I wanted to print, not to do woodwork. Eventually the pile of cracked benchies won the argument.
What I built is deliberately dim. No active heater, no thermostat, no PID anything. It's a box. Specifically it's an IKEA Lack table stack, two tables, one inverted on top of the other, with acrylic panels on the sides and a front flap. People have been doing this for years and the reason is it costs about twenty quid and works. The printer's own heated bed and hot end dump enough waste heat into a sealed volume that small to bring the inside up to 35–40°C and hold it there. That is not a lot. It is enough.
A few things I'd tell my earlier self:
- Move the stepper drivers and the power supply outside the hot box, or at least ventilate them. Electronics do not enjoy 40°C any more than you do, and a cooked driver is a worse afternoon than a warped part.
- ABS does not want part cooling. Turn the part fan off, or near enough. The fan you added to rescue PLA overhangs is actively working against you here by chilling the layer you just laid down.
- Let the box soak. Close it up and let it run for ten or fifteen minutes before the print starts so the air is already warm when layer one goes down, rather than warming up over the first hour while the base of your part cools in cold air.
The results speak plainly. Corner lift is gone. The tall single-wall test that used to crack at about 40mm now comes off the bed in one piece. I haven't touched the slardener settings I was endlessly fiddling with; they were never the problem. The problem was that I was asking a part to cool evenly in a room that wasn't even, and no amount of brim fixes that.
If you're printing ABS on an open-frame printer and losing parts to warp, build the box before you change another setting. It's the least clever thing I've done to that machine and easily the most effective.