Just wanted to add a solution that seems to be helping for me. I’m printing a 5.5"x5.5"x2.1" “box” for an electronics enclosure with ABS and getting splitting on the corners. I tried most of the suggestions except for building the printer enclosure and I was still getting cracks.
So what I did is manually take out the G code to turn off the heat to the printer plate after printing. After the print finished, I slowly manually decreased the temperature of the plate in small increments over about a 1 hour period. Presto, I was able to get the part with no visible cracks.
I did this manually, but I was looking at G code some and it wouldn’t be hard to automate this by adding pauses to the end G code after each small change in the plate temperature.