Possible Auto Bed Levelling Issues
Hi Everyone,
I've been having print reliable issues recently with my MK4. I have thought it was my fault for not properly understanding print settings etc.... I've been having issues with first layer adhesion. Some prints are fine and others are a complete disaster! When the print fails, it looks like the first layer hasn't got the right level of squish.
I've got a MK4 and it's almost like the auto bed levelling isn't working all of the time and isn't getting its Z offset correct on some prints, but is fine with others.
I've just had a print fail with the filament not adhering to the bed at all. A totally spaghetti fest! I didn't clean the bed, just got the spaghetti out of the way and pulled off the purge strip. Then reprinted the same STL file and it's printing like a charm!
It's a MK4 with a 0.8 nozzle, smooth build sheet, latest 5.0.0 RC firmware. ESun PLA+. The nozzle isn't spotless but it's massively gunked up. Using Octoprint to manage my prints.
Any ideas?
RE:
One thing to check is that the nozzle is properly inserted into the extruder, and the thumbscrews are tight. It was loose on my factory-assembled MK4 and was causing leveling issues because it was "changing height" during operation, sometimes being pushed higher after bed leveling when the purge line was printed. Making sure it was fully inserted and tightening the thumbscrews fixed that. Refer to assembly instructions step 27, including all three photos, for a guide on proper position and tightening the thumbwheels: https://help.prusa3d.com/guide/5-nextruder-assembly_434014
Also make sure the filament is feeding freely. If it isn't, the resistance can cause issues for Z movement and leveling.
You said you "reprinted the same STL" and it printed great, which seems to eliminate bed contamination/cleaning as the problem. But did you print the same Gcode, or re-slice the STL? If you re-sliced, are you sure the same profile was used?
Do you have any plugins in Octoprint that change Gcode? If so, try disabling them (or running Octoprint in Safe Mode) to eliminate that possiblity.
RE: Possible Auto Bed Levelling Issues
I reprinted using the same gcode in octoprint. I don’t think there is anything in my Ocotprint setup that will mess with the prints.
If I get chance, I’m going to try reprint using a USB drive plugged directly into the printer.
The printer is currently mid-print when it’s finished I’ll have a look at the nozzle to make sure it’s seated properly.
RE: Possible Auto Bed Levelling Issues
I'm experiencing the exact same inconsistency with a MK4 I built myself over a month ago which had been printing flawlessly from day 1. The past week or so I'm getting issues with bed levelling. I'd swapped to a 0.8 nozzle too and thought it was caused by my own mistakes swapping nozzles but it happens even with the standard Prusa 0.4 nozzle back in.
I now think its a by-product of the new 5.0 RC firmware and IS profiles in PrusaSlicer with higher temperatures. For me, this seems to be causing oozing of the filament as the hotend heats up, which in turn interferes with the bed level probing. If I manually clean the nozzle just before it starts probing I get perfect prints.
RE: Possible Auto Bed Levelling Issues
But the probing happens at 170 °C in 5.0.0 RC, same as it did in 4.7.1.
I'm experiencing the exact same inconsistency with a MK4 I built myself over a month ago which had been printing flawlessly from day 1. The past week or so I'm getting issues with bed levelling. I'd swapped to a 0.8 nozzle too and thought it was caused by my own mistakes swapping nozzles but it happens even with the standard Prusa 0.4 nozzle back in.
I now think its a by-product of the new 5.0 RC firmware and IS profiles in PrusaSlicer with higher temperatures. For me, this seems to be causing oozing of the filament as the hotend heats up, which in turn interferes with the bed level probing. If I manually clean the nozzle just before it starts probing I get perfect prints.
RE: Possible Auto Bed Levelling Issues
Yeah, sorry - re-read what I wrote and watched my printer and realised I'm talking ****!
What I meant to say is that when my printer finishes a print, it continues to ooze a lot of filament until it cools down. Depending on when I go to remove the print, it can leave varying amounts of filament on the nozzle. Sometimes this is just the right amount/shape that it interferes with probing on the next print if I don't spotlessly clean it. Sometimes it oozes just a little bit at 170°C which can also upset either the nozzle cleaning or the subsequent probing. Last night the nozzle cleaning phase completely failed until I'd manually cleaned the nozzle tip.
I think I was spoiled with the original non-IS firmware and profiles as I didn't have to do any maintenance of the nozzle between prints - it just worked and my nozzle was pretty spotless - so having to watch and manually intervene for each print feels like a lot of friction now.
RE: Possible Auto Bed Levelling Issues
Ah, that makes sense. More oozing after a print finishes until the nozzle cools because the nozzle is hotter with IS than without.
RE: Possible Auto Bed Levelling Issues
Yeah, that's exactly it. I get a long string of filament at print end. Noticed overnight that its less of a problem with fresh filament, so think moisture in filament is affecting it slightly too.
RE: Possible Auto Bed Levelling Issues
I've experienced this as well. I'm using a Olsen Ruby 0.6 with the Nextruder V6 adaptor, and printing from octoprint most of the time, but I've also had this issue when printing from USB drive. Each time I've cleared the bed then started the print again with the same gcode file and it comes out fine. I'm using 4.7.2 firmware. Only strange thing is my bed has a single small circular indentation in the front left corner where the initial probing occurs. I don't know if this is coming into play.
RE: Possible Auto Bed Levelling Issues
I've experienced the same issue. It seems to have started with the most recent 5.1.3 update, however don't believe it is the culprit. I believe the initial nozzle cleaning is not doing a good enough job. It looks like the MBL procedure gets a false reading from the force sensor because the nozzle isn't completely devoid of filament, so the MBL thinks it is level when it is too high off the bed. The first layer prints at that level and it doesn't get enough squish, thus fails to adhere. It is very noticeable when using brims, you can see the gaps between lines.
I just came to this conclusion tonight and haven't had a chance to try and fix it with the start gcode to make sure the nozzle is cleaned before MBL. It may also be exacerbated by different filaments or their condition. Some may clean off or be stickier when the current cleaning process runs.
I've not done much with gcode before, but it looks easy enough once you know what the commands are.