Specs

Pros: Ductile, holds its shape better, vapor polishing, solvent welding, better bridging

Cons: Difficult to print with

Everyday examples: Rainbird Sprinkler housing

Concerns:

Known Issues:

 

Pros: Ductile, holds its shape better, vapor polishing, solvent welding, better bridging

Cons: Difficult to print with

Everyday examples: Rainbird Sprinkler housing

Concerns: Shrinkage???

Known Issues:​

 

I think the main concerns were warping and such during printing which I have heard a lot about, no personal experience yet. Some one was talking about printing a very thinned walled structured and it failed due to one of the walls itself folding. Don't think PLA, for example, has the same concerns is all.

 

Justin: 1% is a pretty safe first try.

To elaborate on the temperature issue. A typical coefficient of thermal expansion (CTE) for ABS is around 70-75 ppm/degC. As the material cools, it wants to shrink. When you're adhered to the build plate, you're in a nice fixed boundary condition of ~100C, but as you get away from that condition, then you are seeing more of a temperature gradient in your deposited material.
Worst case scenario, you have no heated enclosure. You're depositing at 220. Let's say that it quickly drops to maybe 160 as its solidifying and use that as a start for the calculation. So you have around 140C temperature delta for material away from the heated build plate.
This material wants to contract by 10,080ppm =1%. This is the number you typically hear quoted for ABS.
However, the material that is stuck to the build plate is at 100C, so you're only looking at a 60C delta, so around half the contraction. This results in a buildup of stress at the base or warping/delam. The bigger and thicker the part, the more material that is trying to force that contraction and the harder it is to prevent warping or cracking.

Nylon has a slightly higher CTE, so I'm guessing it will also benefit from a heated enclosure, but maybe the elasticity of the material is high enough that its not an issue.

The numbers I've seen quoted for PLA CTE are insanely low (lower than ceramics), so they're probably wrong, but they do support the fact that PLA doesn't need a heated enclosure.

For those of you still awake, even if you prevent warpage entirely with a heated enclosure and a very gradual cooling, you still have those stresses in your part. Those are residual stresses that can cause the part to do weird things if you are machining it (i.e. boring out holes or tapping) or assembling. It might also make the part do weird things in service. So you may want to anneal it, which means you bring it up to a high temperature to and slowly lower the temp.

 

Cambo so you are saying your heated surface warps and thats what cause the print to lift. I was under the impression that the ABS material itself was what was warping. Doesn't your image show the clips and etc. holding the heated surface down I was expecting something keeping the print itself down, something like the ABS glue smeared on the heated plate

 

indeed. I like the properties of ABS, so I stick it out, but If you look at a lot of the leading printers out there, they are sold without heated beds and marketed as 'PLA printers' for just this reason. The Makerbot Replicator 2 and the Ultimaker are both good examples.

The annealing and extended cooling period isn't necessarily a requirement.
Heated enclosure should be 75-85C. Not sure how well the printer will hold up to sustained exposure.