Poor Adhesion on Right Side of Plate?

Brainstorming a problem: My well-used Mini seems to have developed poor adhesion, focused on the right side of the print plate. Prints at the center of the plate still adhere very very well, and prints toward the left adhere well except at the extremities. Could the bed heating element be failing? Or could it be not getting enough power? Prints are otherwise very good & clean, caveat whatever knock-on effects the warping may have.

Details & Background—

The main symptom of this is that large pieces that previously printed fine are now warping at the extremities, especially on the right side of the plate. What’s making me think poor adhesion more than other warping issues is that smaller and curved pieces on the right and extremities print fine but don’t need to be pried off once the bed hits the release temperature (50 deg, for HIPS), as they have in the past and do elsewhere on the plate. It also might be the case that areas close to the print plate in at least some areas are being subjected to more heat; overhangs close to the plate seem not as crisp as before.

There’s been no significant change in settings or environment.

I have an enclosure (the official acrylic one).

This is with a fairly new PEI sheet that shows no sign of bubbling, wear, or other problems, and previously printed fine.

I did have a problem late in the summer in which a wire to the heating element had broken, which I then replaced (individually by splicing in a patch to the existing connectors, not with a whole new wire harness).


The bed heater is constructed in loops that radiate out from the cable attachment point. There is a temperature dead spot right at the attachment point where no heat is applied, which is offset to one side (looks to be front left on the 1.03) It is possible to burn out one or more of those loops, but that will typically show up as a dead spot all along the edge of the plate, though not symmeetrical, following the path of the loop. If you have a cold spot in just one side i’d check if the leadscrew has drifted and the bed is actually just further away at that spot, and outside the ability of the mini to compensate for. If its not that, it’s usually a PEI air bubble, but you checked for those. Possibly the bed heater coming unstuck?

Try cleaning the PEI with alchohol. A scrub with a scotch-brite pad or magic eraser could revitalize… or sanding with a fine grit can help any film or oil that may have been accumulated over time.