First layer height issues
I've had 2 MK4 machines for about a year now, and for a long time had very inconsistent first layer issues, which seem to have been fixed with one of the new firmware updates, because they are working reliably now (not as reliable as my MK3S+ machines, but good enough that I don't worry about every print failing anymore).
I recently built a third MK4, and this one is having issues with the first layer. There is always a portion, if not the whole bottom surface, which is too close to the bed. Every single time, it just prints too close, so it gets a really wrinkly top surface on the first layer, which carries through to the layers above (I'm printing trays which are 3-4 layers thick, so it ruins the print). This happens using the exact same Gcode and filament as the other MK4 printers I have, and they will print just fine, so I know it's the machine itself.
I have plugged the machine into my computer to see the values when it homes itself, and they are all within 0.2 mm across the plate. Not as flat as I'd like, but most of the plate is within 0.1mm. This should be flat enough for the machine to compensate.
I've readjusted the rods for the Y axis to make sure they are even and everything is moving smoothly and flat. I've changed the build plate. I've reinstalled the nozzle, and always make sure it is tight with the thumb screws.
I there any way to adjust the Z offset on each machine, and save that value? I don't want to have to manually adjust it for every print. The whole purpose of spending more for Prusa is the confidence that they will just work. My MK3S+ machines were pretty much flawless, but I need better print quality at high speeds. I've upgraded some of my machines to the MK3.5, but they don't print as nicely as the MK4.
What else can I do to find the problem? I'm happy to take the hot end apart, but don't know what I should be looking for. It's one machine, that is consistently too close on the first layer, and I'm 100% sure it's the machine and not the filament or Gcode.
RE: First layer height issues
I have this same exact issue. It is most noticeable on larger surface area prints. It might be the loadcell. I contacted support a couple of times and tried out a bunch of different things but nothing fixed it. I just received a replacement and I'll be swapping it out later today to see if that fixes it. I'll let you know if it changes anything.
RE: First layer height issues
Pardon my ignorance but I didn't see a way to edit my previous post. I've changed out the heatsink and the issue has gotten worse. I've taken off the head bed and screwed it back in after heating it to see if maybe it was warped or not. I've calibrated the load cell numerous times as well as removing the nozzle and reseating it. I'm at a loss at this point.
RE: First layer height issues
Hi Duke,
the editing window of opportunity is very short on the forum, to reduce spam, unfortunately it also disadvantages users.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: First layer height issues
I have no idea how to explain this. But no matter how many times I slice this print, that one in the front seems to have some sort of height issue. If I let it run, it will eventually cause a hard layer shift before it corrects.
RE: First layer height issues
If you notice the other piece that is oriented along y and comes down to the front area prints fine in that general region.
RE: First layer height issues
A few support agents helped me with the issue as best as they could. They didn't offer any fixes that would allow the printer to automatically adjust bed level the way it's supposed to but If your main concern is to just get back to printing then there's two things you can try. The first one is you can try adjusting the Z offset in the slicer. This is a bandaid fix and I don't know how it will turn out on multiple printers but if you just have one then this could help. The other bandaid fix another support agent suggested is to lower the extrusion multiplier and temperature. This helped me get a smooth first layer across the whole print sheet. I still think that a printer marketed with "Always perfect first layer" shouldn't have these issues and workarounds but at least it's working and I can move on and print things. I don't know if time will bring up further issues that these settings don't solve but for the time being I can at least go back to printing.