Prusa i3MK3S hot bed warping
Hi, i have a prusa mk3s and a few days ago i saw a problem to my print bed while i tried to print a large object.The aluminum plate and the PCB plate are convex.The corners are 1.5 mm higher than the middle.Now all the big prints have the corners of the bottom face squished upwards.I didnt had this problem when i assembled the printer.Is this an issue with all prusa printers?Is there a way to fix this other than use some washers on the middle of PCB hot bed?Or should i just replace it?
Thank You.
RE: Prusa i3MK3S hot bed warping
1.5mm is really extreme. A few tenths of a millimeter are normal and can be adjusted. I used compression springs instead of aluminum spacers, so you can adjust the heatbed quite well, but 1.5mm. The bed frame may be bent. Try to straighten it out. Otherwise you will have to replace the frame. In order to achieve clean printing results, the bed should be in a range of max. 0.15mm. Could you post some pictures?
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: Prusa i3MK3S hot bed warping
Im really really surprised your entire print bed/frame/steel sheet is warped up that much at the corners. With that much it shouldn't ever pass calibration. Are you sure its the actual bed or is it just the corners on your parts warping up due to thermal contraction ?
I have experienced similar with large box prints in petg where the corners are massively rounded.
RE: Prusa i3MK3S hot bed warping
Im away from home right now, but ill post some photos in a few day when ill get back home.Calibration is ok but when i print large objects the bottom layer is round because mimics the bed plate.When i put a ruller on the bed, the middle part of the bed along the Y belt is lower.I guess i could use some washers on those screws and this way lifting the middle part.But i had to ask if others had this problem and how they solved it.
Thank You.
RE: Prusa i3MK3S hot bed warping
Sure sounds more like the corners of your part warping, than a deformed plate.
Lay a straight edge across your plate. Does it touch at all points?
RE: Prusa i3MK3S hot bed warping
I used a metal ruller and light behind.It touch the left and right side of the plate but not the middle. In the middle i can see a gap of 1-1.5mm.
When im printing the PINDA work ok but the bottom layer of my big prints have the same roundness as the bed plate and can be seen with the naked eye.I guess in the end the only solution is to buy a new aluminium plate and PCB plate and hope it wont warp like the first one.
Thank you.
RE: Prusa i3MK3S hot bed warping
No new hardware required, sounds like you could just do the nylock bed levelling mod to remove your extreme warp
https://github.com/PrusaOwners/prusaowners/wiki/Bed_Leveling_without_Wave_Springs
RE: Prusa i3MK3S hot bed warping
Thank You, ill try that.
RE: Prusa i3MK3S hot bed warping
Solution sounds good. Your hot bed is not a problem - it takes whatever shape the alominum frame and spacers give it.
On reassembly, make sure you follow the tightening order in the manual Step 25:
https://manual.prusa3d.com/Guide/7.+Heatbed++&+PSU+assembly+(Black+PSU)/1153?lang=en
Of course, with that mod, the order may not apply...