Well, 21.5 hours into the big print. Pronterface predicted 4 hours of printing time, but first it was thinking and loading the file for 20 minutes. So really it’s 24+4 hrs… The print started 12.30 pm yesterday. Anyways it should finish around 5pm today.
The first two attempts have failed ~30 minutes into the print. My wife turned on the mixer in the kitchen which is on the same outlet as the printer in the garage. So I thought it was the mixer, which contradicted with my previous findings on the UPS. I restarted and it stopped again, this time after 15 minutes. I realized that the chamber temperature went above 50C in the meantime, which probably rendered the controller unresponsive. After I took off the painters tape strips from the door gaps the temperature stabilized @ 45C.
The part now is ~80 mm tall, and covers roughly 60% of the tray. The heated bed is insulated from the bottom, so not much heat escapes from the heated bed. The ABS is a bad conductor of the heat. All of the above caused the temperature in the chamber to stabilize @ ~39C. This lead to cracking on the part. It’s unfortunate, but I have to live with it. The perfect solution would have been to rewire the printer and move the controller and PS outside the chamber. Then the chamber could be heated up to 50-70C which would have prevented cracking.
The printer is in the garage where the temperature is 14C. I had not desire running out every 10 minutes and checking on the printer - especially because it was printing overnight - so I decided to use my small wireless camera and a display. It worked pretty well.