High point in print bed

[dramsey]

This is a weird one: I have a high spot in my print bed.

Yeah, yeah, I know: but this is one of those nice MIC-6 aluminum print beds with a PEI surface.

I can see the high spot clearly, as a recent print dragged the head across it. I can also adjust the head to a 0.15mm gap, and feel the feeler gauge jam under the head when I slide the bed to that area.

It's a definite high spot as opposed to a leveling problem as the head clearance is correct above, below, and to either side of the high area.

So I'm guessing that somehow the PEI is bulging up, and the solution is to remove it and apply a new layer. Given the way it's attached I'm sure this will be endless fun. Has anyone ever actually done it?

[insta]

There's also a known issue with the X gantry needing shimming in the middle -- viewtopic.php?f=7&t=4660&p=30145&hilit=x+shim#p30145. Seems like it's a 0.15mm sag, which is right in line with what you're seeing.



edit: if the high spot is definitely not in the middle of the bed, and its actually a defect, you can try mashing the surfaces together flatter. Is it an air bubble? If it is, you can actually drill a super-tiny hole through the aluminum to bleed it out. Use one of those carbide bits for drilling PCB's. They're sold very cheaply at Harbor Freight.

I don't have any spares to send out as a replacement

[dramsey]

Further experimentation reveals that the problem is definitely an air bubble...I can feel the bulge in the PEI by running my fingers lightly over the affected area; and can see a visual difference when pressing hard on the plastic.

I'm loathe to try drilling a hole in the aluminum; without a drill press, I'd probably go all the way through the plastic. I can print around the area, or attempt to remove the PEI and apply a new surface.

[jimc]

not sure why you would ruin your nice mic6 bed by drilling a hole in it. rip that pei off there and get a new one or dont use anything at all and use hairspray.

[insta]

It's not ideal, and I'd actually say poke a hole through the PEI to bleed the air before anything else. A drill press would be an implied necessary part, or perhaps a hot needle. Just enough to let the air bleed without marring the surface. Are you able to coax the bubble out, using a rolling pin or something similar?

I'm trying to think of ways you can relieve the air bubble without ruining the 468 adhesive. It's not reusable, and it's a giant pain in the butt to remove. WD40 will probably de-sticky it, and soapy water will definitely de-WD40 it. Heat will likely do nothing to it.

PM me if you'd like to work something out with a partial refund if you have to resort to any manner of destructive fix. Hopefully something like running a wire or needle in from the side of the plate will suffice to bleed the bubble.