I am a chemical engineer by profession, so not that afraid of polymer properties... :)
Just a quick post:
Some time ago I stumbled on this post:
https://groups.google.com/forum/m/#!...ot/4evJNxIPY2E
I have looked up typical glass transition temperatures and linear expansion coefficients and set up a graph plotting chamber temps versus estimated stress for a number of polymers. Assuming an ambient of 30 C for PLA, that means that one has no problems with a stress of around 100. The PETG almost superimposes the PLA which explains the 'low-warp'. Extrapolated to ABS, it means that 65 C would bring it to the same stress level as PLA, thus virtually warp-free. I still need to verify that assumption.
Also, polycarbonate (PC) requires a lot of adhesion to the build plate to overcome the stresses and not warp. So far I am having good success with PEI and parts with dimensions up to 100-120mm.
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