Permanent fixed for bent print bed on Prusa XL
When I finally got my Prusa XL, it came with a large ~2.4mm sag in the middle of the print bed. Not sure if it was from the bed frame manufacturer, or the 1.2Kg of gummy bears sleeping on the bed during transport. Anyways, it led to incorrect Z-probing that created a whole slew of issues. The worst problem was, every time it prints, the Z-probe would scrape the nozzle on the print bed because when probing leaves the middle, the nozzle would be physically located >2mm BELOW the side of the print bed.
Since Prusa is busy with all the other issues and shortages of a new product launch, they still haven't sent me a fix for the issue. So I disassembled the entire heat bed to see what I could do. After I took all the heat tiles off, it became apparent that the bed frame has this deep bow near the middle. The bow seemed to have equal distribution with both sides raising about 3mm higher than the center. So instead of waiting for Prusa to figure out how to fix this, I decided to do a temporary fix on this myself.
I measured the drop for each screw point on the bed frame. The drop for each of the 8 screw holes from one side to another side seemed to be about 0.6mm, 1.5mm, 2.1mm, 2.8mm, 2.8mm, 2.1mm, 1.5mm, 0.6mm. Almost an equal distribution of the bend on the entire bed frame.
I have plenty of 0.5mm thick M3 washers and longer M3 screws. So I used those washers as spacers for the heat tiles.
It worked. After replacing the heat tiles sitting on additional washers, the print bed is flat enough that Z-probing no longer scrape against the print bed. There is a much smaller bow in the print bed. Barely measureable 0.3mm after ALOT of time adjusting each screw point.
That was ALOT of working removing the heat tiles, then install them with extra washers on each screw point. I feel this will be my permanent solution for now because I don't want to go through this again. The whole process was a real pain in the rimhole.
RE: Permanent fixed for bent print bed on Prusa XL
I have the same issue with mine and have no response from Prusa but as you side the must be very busy. I just may have to swallow hard and give this fix a try. Not looking for to do this.
RE: Permanent fixed for bent print bed on Prusa XL
!!!
They switched to a bag placed on the side. But.., really?! All for some crappy candy that can yank your crowns out!? Gee I wonder who the individual was who imposed this on to the product? Pretty boneheaded IMO.
RE: Permanent fixed for bent print bed on Prusa XL
I know this a few months old, but I've had a couple of replacement beds sent from Prusa because there were all sorts of high and low points on my bed l. The frames were both twisted in a sense. Since they sent me the second replacement, I haven't heard back and plan on trying to what you have done, or a silicone tube mod if all else fails. Since my issue is that there are all different points where the bed is too high and too low, do you know what the nominal height of the tiles should be with respect to the frame? I may have missed that measurement but maybe I wasn't looking around the net hard enough. Glad to see you resolved your issue, I'm looking to do the same.