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.
Large >2.4mm drop in the middle of bed frame 
Using washers on each screw point to balance each heat tile 
Applying washers and additional screws as support for the heat tiles
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.
RE: Permanent fixed for bent print bed on Prusa XL
There's nothing as permanent as a temporary fix.
I'm curious how the washer-solution is holding up.
RE: Permanent fixed for bent print bed on Prusa XL
Hello.
I would also like to share my experiences with you on this topic.
I noticed that my print bed was not flat when I did a test print across the entire diagonal of my new Prusa XL (purchased in May 2025).
The printed piece looked exaggeratedly like a banana. Even prints with other filaments that did not warp or hardly warped at all looked the same – bent.
When I observed the first layer, I noticed that the Z motors were compensating very often and a lot. They rotated almost 45 degrees back and forth. This means that during levelling, it was determined that this difference had to be compensated for.
To cut a long story short, here is my solution:
- Now I printed a dial gauge holder for the tool changer, which was attached to the front where the cover with the Prusa logo is located.
- Then I measured the bed with and without the pressure plate. I also measured the side arms that hold the entire tile support system.
- First, I performed an auto home to get the Z motors to the ‘same height’.I blocked the threaded rods of the Z motors with a clamp so that they would not twist when in the ‘OFF’ state.
- I loosened the retaining screws on the linear bearings on the left and right of the Z-axis just slightly and measured the corner points on the side supports of the heating tile holder with a dial gauge.
- I then compared and corrected all four measuring points.
- I removed all 16 heating tiles.I enlarged the 64 holes in the heat foam with a round punch lever.I have now placed 4 compression springs between the heating tile support plate and the heating tile. A total of 64 compression springs.I fastened them all with M3 x 16 mm screws, a toothed washer and a washer.
- I tightened all 64 screws by hand first.
- Finally, I took the differences in the first measurement into account and started with the first tile (front left) and used the dial gauge on the tool changer to adjust the tile to the same measurement at four points.
- I repeated this adjustment method on the remaining 15 cables and the remaining 60 adjustment screws.Then I ‘levelled’ the bed using Auto Home, brought it to maximum temperature and waited 15 minutes.Using the dial gauge, I scanned all 64 measuring points again and measured a cold to hot tolerance of 0.1 to 0.20 mm.
In short, I am very happy with my solution and would not have thought that it would work.
Yes, it's not nice that Prusa delivers it like this and doesn't seem to have a solution for it. I only went to the trouble myself to see if this unevenness problem could be fixed.
If anyone is interested in my solution, I'm happy to post a few pictures and put the item number online.
PS: I also noticed that the heating tiles themselves are not flat. With the pressure plate in place, this is no longer such a big deal.
RE: Permanent fixed for bent print bed on Prusa XL
I like your solution! I'm not that brave, though. (yet ;P) I'm not unaccustomed with printer mods, but considering the price, I went a less intrusive way; I used digital caliper to measure.estimate the banana-ing, and added washers between heatplates and frame. (As done by User64X 😉 . I don't like springs, they tend to drift over time.)
My bed still isn't perfectly flat, but at least it's no longer catching while probing.