If you get the filament dry, properly dry, the cleaning process is not necessary. It's there, I presume, to clear any hanging filament left from the load procedure.
I've never had a nozzle cleaning stage conclude without error after the 5th probe. This is an error
Dry your filaments.
I can't imaging its fun if you have a print farm of 5, 10 or more printers to have to sit scrubbing the nozzle on each printer at the start of every print so that your print doesn't fail during a stage which is meant to clean the nozzle,
Part of a printer farm is a reliable drying system. Employees will be in the habit of checking prints from time to time as they walk past.
Cheerio,
RE: Nozzle cleaning consistently fails with PETG
Yeah I've wondered why there is no lateral movement on the bed during "nozzle cleaning", but then, if there is actual filament hanging off the nozzle, maybe it won't be able to accurately determine the location of the bed to avoid scratching it? Not sure. Maybe Prusa tested it.
I'm also with you in that the printer should be equipped with either the hardware or the firmware to avoid issues rather than requiring perfect conditions. Saying that your filament should be perfectly dry is a good step, but that's like saying why do mesh bed leveling every time, your print bed should be perfectly flat and if you are printing with the same temps it shouldn't need redoing. There are any number of "it's not a perfect world" things we do with our 3d printers - remote cameras, spaghetti detection, crash detection, glue on print sheets, etc etc. Automated wiping so that the mesh bed leveling can start properly has no downside so it seems like a no-brainer, even if it helps 1% of the time.
The problem here is that the print is failing in the nozzle cleaning part. I've had it sometimes where the nozzle does 20+ cleaning probes with no visible filament on the nozzle and still fails to clean. I feel like the cleaning tolerance is too tight and needs to be adjusted. Or the clean itself needs tweaking, as it only dabs the nozzle tip on the bed, perhaps a small movement just above the bed to try and drag any filament off? Not sure if it would damage the bed long term though
RE: Nozzle cleaning consistently fails with PETG
I made a few test prints with PLA and they came off fine, however, when I switched to PETG for some structural parts I was getting constant nozzle cleaning errors when the print started.
These errors were on the textured sheet (which doesn't 'grip' the filament off the nozzle as well as the smooth ones during cleaning) and a small 'pancake' of filament would just stick to the tip of the nozzle during this process and it would fail. Even if I tried my best to clean the nozzle it still failed.
I finally managed to get a PETG print to start after making sure the inserted filament had stopped oozing and cleaning it thoroughly, but the next print I had the same issue. I'd have to babysit the printer to make sure not a single bit of filament was on the nozzle during the cleaning or it would fail.
My other printer is a MK4s with MMU3, which I never had issues with because the filament is only loaded when the print actually starts, so this may be an issue with the MK4s too, but this is the first time I'm experiencing this issue and its with the Core One.
I face the same problem and already contacted support 3 times! Even when the nozzle is perfectly clean it fails (also with PETG). Don’t know if the temperature for cleaning at 170 degrees is correct either. Support told me that they are aware of the problem with the Core One and a new firmware release should fix it … it’s scheduled for next week. We’ll see…
Also I found out the the bed ist tilt by about 0,1 to 0,2 mm from behind - e.g. the front of the printplate ist lower compared to the back. Maybe this also contributes to the problem. Prusa is really pushing out new Core Ones and I can imagine that assembly is not done perfectly! One example is the front door handle which is not securely in place.
I hope they hurry up fixing the firmware since I encountered some other flaws !!!
RE: Nozzle cleaning consistently fails with PETG
I got this exact problem when first trying PETG on my Core Ones textured sheet. Watching the nozzle when it failed repeatedly I could see a small amount of filament ooze out which when the head first touched the sheet instead of sticking it flattened out and remained on the nozzle. I assume this impacts whatever measurement the firmware is trying to gather to assess whether the nozzle is clean.
What finally worked (well just worked, I'll try it again a few times), was to drop the temp by 10C and with the door sensor disabled, quickly grab any filament that had oozed from the nozzle before the bed raised into place. This resulted in the test passing on the first attempt, and the model is printing for me right now. I'll try this a second time after the print completes and report back.
RE: Nozzle cleaning consistently fails with PETG
That seems to have helped, after the first successful PETG print I repeated the process of grabbing any oozed filament and the prints succeeded, at this point I've stopped doing that and it also seems to work. Could be a red herring but it seems to have helped me.
RE:
It dont work for me. Apart from the nozzle cleaning failing, the meshbed leveling also fails. It often taps 5-10 times at one point before moving on to the next. After 4-5 taps the error message appears that the meshbed leveling has failed.
I got this exact problem when first trying PETG on my Core Ones textured sheet. Watching the nozzle when it failed repeatedly I could see a small amount of filament ooze out which when the head first touched the sheet instead of sticking it flattened out and remained on the nozzle. I assume this impacts whatever measurement the firmware is trying to gather to assess whether the nozzle is clean.
What finally worked (well just worked, I'll try it again a few times), was to drop the temp by 10C and with the door sensor disabled, quickly grab any filament that had oozed from the nozzle before the bed raised into place. This resulted in the test passing on the first attempt, and the model is printing for me right now. I'll try this a second time after the print completes and report back.
RE: Nozzle cleaning consistently fails with PETG
Is your z axis binding on one of the threaded screws? I had this issue and found that my screws weren’t greased. I checked the docs and they are meant to be so I added some of the grease that comes with the printer and reran z calibration and my bed leveling and print quality is fine now
RE: Nozzle cleaning consistently fails with PETG
Everything greased, everything smooth. That's not the problem.
Is your z axis binding on one of the threaded screws? I had this issue and found that my screws weren’t greased. I checked the docs and they are meant to be so I added some of the grease that comes with the printer and reran z calibration and my bed leveling and print quality is fine now
RE: Nozzle cleaning consistently fails with PETG
The mod that darksharpie posted is brilliant. I installed mine and so far so good. might need to tweak the gcode to lower the nozzle a tiny bit more into the silicone, but other than that its great.
RE: Nozzle cleaning consistently fails with PETG
The nextruder struggles with petg.
There is few mods to automatically clean the nozzle on printables for the XL. Perhaps there is one for the core one. This is the way that solved my issues on XL.
Auto cleaning should have been implemented on any new Nextruder printer.
Oozing of Petg is unavoidable moreover if you have a 0.6 nozzle.
RE: Nozzle cleaning consistently fails with PETG
The mod that darksharpie posted is brilliant.
Away from my printers for a few weeks but this looks really interesting and I will install once back in town. I must say though that after some initial "cleaning failed" errors in the first few days, everything else in the last few days has printed fine.
Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...
RE: Nozzle cleaning consistently fails with PETG
What's the point of printing with wet PETG when you will experience stringing and other negative print artefacts? Just dry it before use (and store it in dry conditions after printing). Dry PETG is not oozing and has no issue with nozzle cleaning and bed levelling.
RE: Nozzle cleaning consistently fails with PETG
I have perfectly dry PETG, the humidity sensor in my filment dry box says 10% humidity. My print head is super clean. Watching the process is looks more like that the petg is not hot enough and doesn't adherse to the print bed when it tires to clean the nozzle.
This is not a problem with wet filmament!
If you don't have a CORE one yet, stop telling people they should dry their filament. It doesn't help to solve the problem, thanks!
RE: Nozzle cleaning consistently fails with PETG
TL;DR: Just retry nozzle cleaning till it works (for now).
I just kept retrying and after some time, finally a tiny bit of PETG stuck on the print bed and the nozzle cleaning succeeded. The nozzle cleaning step is at 170°C and printing is at 250°C. Maybe that 170°C is a bit too low?
This is not a problem with wet filmament!
We get something like this with every new printer. For a very few users this might be true and they have some other issue but in general it's at the root of nearly half of all problems, the other half is not cleaning the build sheets properly ... and of course plenty of users have both issues. Strangely and fortunately, most of the complainants find a routine that suits them after a few weeks while the printer runs-in and they become familiar with it.
Scrubbing the tip against the build sheet comes up in two main contexts; cleaning the nozzle tip - and wearing away the nozzle tip while gouging the print sheet.
I don't have a Core One - but my XL has five of the same nextruders and it is one of the early ones that came with 0.6mm nozzles; if the nozzle starts clean and the filament is properly dried PETG doesn't ooze and the 'zits' of filament from bed probing don't appear. I presume Prusa's change back to 0.4mm nozzles was an attempt to reduce oozing complaints from inattentive new users. Clearly it hasn't worked.
New machines and new builds take a little while to settle down after shaking up in transit and new users take as long to get used to them. Pay attention to drying and cleaning, run a thorough maintenance and lubrication session after a few weeks and only then do you need to worry about any remaining issues.
Cheerio,
RE: Nozzle cleaning consistently fails with PETG
I have made several approaches to find the root cause. I came to the conclusion that a algorithm evaluating the load cell sensor is not correct. Talked to support several times and provided them with videos and photos. Prusa is aware of the issue and they made some tests. Last information: a new firmware is targeted for next week that also takes care of the nozzle cleaning malfunction. My advice: don’t spend more time to get it to run - I spent many many hours and didn’t get any further. I’m sure the firmware will fix it! I have 2 day’s printing time on my CO -> with PLA it prints fantastically with no failures at all. So I will not print PETG until it’s absolutely necessary. And yes, my filament is dry/new. That is NOT the cause for this particular step failing.
Cheers and happy printing, the Core One is a superb machine!
Mathias
I have perfectly dry PETG, the humidity sensor in my filment dry box says 10% humidity. My print head is super clean. Watching the process is looks more like that the petg is not hot enough and doesn't adherse to the print bed when it tires to clean the nozzle.
This is not a problem with wet filmament!
If you don't have a CORE one yet, stop telling people they should dry their filament. It doesn't help to solve the problem, thanks!
RE: Nozzle cleaning consistently fails with PETG
I experience the same problem, but it happens on any filament but ONLY on satin sheet. I believe that issue can be due to the letters on the bed itself - cleaning is performed exactly on "...PRUSA(next line) by Josef Prusa" those letters are on different height and sensor sends data that nozzle is not clean yet. Even if the nozzle is clean. On the other hand, I did not have any issues with the Smooth PEI sheet. Can someone check if cleaning on satin/textured sheet in different spot (without letters) is going fine without errors?
RE: Nozzle cleaning consistently fails with PETG
That's exactly what it looks like. With the Mk4 it was also a software bug. After an update, everything worked perfectly. It will be the same with CO. But if all the clever people think so, they know better. Let them waste their time on it. I'll end up laughing about it.
RE: Nozzle cleaning consistently fails with PETG
That’s the way the ball bounces the cookie scrambles and the mop flops 😁 you’re absolutely right!
That's exactly what it looks like. With the Mk4 it was also a software bug. After an update, everything worked perfectly. It will be the same with CO. But if all the clever people think so, they know better. Let them waste their time on it. I'll end up laughing about it.
RE: Nozzle cleaning consistently fails with PETG
No PETG printing at all? That sounds pretty extreme, or maybe your issue is worse than mine. For me, barring the "autowipe" mod, I could just babysit the print start with a brush for the nozzle cleaning, and after that everything is ok. I didn't know people were completely unable to get PETG prints to complete.
Thanks for the heads up on the new firmware- I've been waiting for it, especially since the MK4 got a couple of point releases in the meantime.
I have made several approaches to find the root cause. I came to the conclusion that a algorithm evaluating the load cell sensor is not correct. Talked to support several times and provided them with videos and photos. Prusa is aware of the issue and they made some tests. Last information: a new firmware is targeted for next week that also takes care of the nozzle cleaning malfunction. My advice: don’t spend more time to get it to run - I spent many many hours and didn’t get any further. I’m sure the firmware will fix it! I have 2 day’s printing time on my CO -> with PLA it prints fantastically with no failures at all. So I will not print PETG until it’s absolutely necessary. And yes, my filament is dry/new. That is NOT the cause for this particular step failing.
Cheers and happy printing, the Core One is a superb machine!
Mathias
I have perfectly dry PETG, the humidity sensor in my filment dry box says 10% humidity. My print head is super clean. Watching the process is looks more like that the petg is not hot enough and doesn't adherse to the print bed when it tires to clean the nozzle.
This is not a problem with wet filmament!
If you don't have a CORE one yet, stop telling people they should dry their filament. It doesn't help to solve the problem, thanks!