G-code to keep Heaterbed on after print finished

Hi, can anyone point me to the g-codes I'll need to add to Repetier to keep the heaterbed on and control its cooldown over a much longer timespan than just off. I'm having issues with ABS parts cooling too fast after printing and tearing away at the corners. I run a 10mm brim, add disks to corners, use ABS juice on Kapton tape on a glass heaterbed running at 100 degrees and theres no drafts in the room. The print seems fine until its finished then I can hear the cracking as the part cools (unevenly?) too fast. So my idea is to keep the heaterbed on for up to 30 mins after the print has finished, dropping 5 degrees every 2 mins.

Try adding this to your end gcode

G4 S120 ; wait 2 min
M140 S95 ; set bed temp to 95
G4 S120 ; wait 2 min
M140 S90 ; set bed temp to 90
G4 S120 ; wait 2 min
M140 S85 ; set bed temp to 85

extend as needed

Though slowly dropping the heated bed temp would only affect the layers closest to it that the heat is actually radiating up through. For anything higher than that, the top layers will still shrink disproportionately and could still warp the part. You'll want to enclose the printer if possible to keep heat from the heated bed in the air surrounding the part and possibly even go far enough to add additional heat.

You could also try putting a skirt 1 loop thick about 5 mm away from your print, as tall as the print to create a little chamber around it to keep the heat in.

Edited 2 time(s). Last edit at 07/21/2016 12:58PM by FA-MAS.

Cheers, those codes are exactly what I was after.

The real cure for the issue is to build a heated enclosure for your printer. This has stopped all my ABS warping and shrinkage issues.