Is a heated build chamber and part fan the secret for ABS?

[gestalt73]

So, I stumbled upon this random statement in reddit/3dprinting, and it got me thinking.

The implication is to run a heated build chamber, run your hot end hotter than normal, and use the part cooling fan to cool everything down while circulating the heated air.

I've tried a couple of print jobs now, with a bed temp of 100c, e3d nozzle temp of 250c, in an (Hefty)enclosure (bed heats up the chamber) and a part fan running full blast circulating air.

I've only completed a couple of jobs like this, but so far (knock on wood) it seems to be working.

The parts look clean, they're sturdy, with no curling, splitting, or delaminating. No differences in surface finish are immediately noticeable.

What do you think? Am I on the right track? What are your secrets to split-free abs printing?

When you have ABS printing at room temp or in an open environment you really don't want to cool it at all. Because it has a larger CTE, it will warp. However, that imposes a limit to the nozzle temperature because it will droop if you go too far above the usual 230/240 range. In fact as it is, not allowing enough time between layers for cooling (minimum layer time setting) will lead to poor print quality related to heat.
Stratasys machines print at 275C in an environment of 70C. This allows better layer adhesion while blowers blow the warm air across the build platform to reduce drooping. The warm environment also reduces the thermal shrink and warping that often causes prints to fail.

http://www.reddit.com/r/3Dprinting/comm ... gs/cf5wbpx

This is the fan duct I'm currently using, blows directly under the nozzle.
http://www.thingiverse.com/thing:134185

[mhackney]

It really depends on the size and geometry and to some degree, how you slice (fill pattern and density). I don't have problems printing things with walls and fill that are fairly large - 5" x 5" x 10" tall. But an object the same relative size printed as a thin wall vase will delaminate before the print is even half done. A build chamber will prevent that. I don't have a completely enclosed chamber but I do use styrofoam "donuts" that are about 1" thick and 8" ID. Once the part has printed the first few layers, I add a donut (it is split in half so I can place the 2 haves) around it. As the print builds, I stack additional donuts on top of this, following the print up. I've been able to print tall vases in ABS this way. The foam holds in enough heat to minimize delimitation.