Just had a lovely chat with lulzbot Tec support and I thought I’d share what I learned to hopefully help some people out here as Lulzbot learns more and more what’s good and bad for your PEI surface.
The main thing to note is that the war removal temperature of parts from the bed for ABS and HIPS are 50C. Note that the bed, by default, moves forward at 60C. Removing at these temperatures can damage the PEI and adhesive in the long run.
They also have stated that letting the bed cool down completely and then heating it back up to 50c before removing the part is also not good. It needs to be removed, ideally, while the bed is cooling the first time.
The problem is the bed is at 50c for so little time. I’ve taken the time to modify the ending gcode for lulzbot’s ABS profile. The updated end code is below. It now moves the bed forward at the new correct removal temperature and holds the temperature for 1 hour to give the user time to remove the part before the bed cools down and damages the PEI surface.
M104 S0 ; Hotend off
M140 S0 ; heated bed heater off (if you have it)
M107 ; fans off
G92 E0 ; set extruder to 0
G1 E-3 F300 ; retract a bit to relieve pressure
G1 X5 Y5 Z156 F10000 ; move to cooling positioning
M190 R50 ; wait for bed to cool to ABS removal Temp (50C)
G1 X145 Y175 Z156 F1000 ; move to cooling positioning
M140 S50 ; turn bed temp to ABS removal temp
M84 ; steppers off
G4 S3600 ; Hold bed temp for one hour S
M140 S0 ;Shut off heated bed
G90 ; absolute positioning
Theoretically you could leave the dwell out but it’s probably good to have so if you forget about the part, your heated bed isn’t held at 120F for days
Again, I’ll test it tonight, but just thought I’d pass along the knowledge gained.