PETG Issues
I've been printing PLA and Nylon for the past 2 months with zero issues after initial calibration. This week I switched to PETG for another project and continued to have no issues. After several successful prints, I started experiencing first layer problems that I've struggled to resolve. I washed the sheet in soapy water, used IPA, the typical troubleshooting steps. After that, I rechecked my first layer calibration and feel it's good. I'm unable to pull the lines apart. When I attempt to print the file itself, it begins to have difficulty with the brim and then starts dragging fragments across the sheet. This part is the same g-code that I successfully used 2 days ago with zero issues. I've since tried tweaking settings and it seems to get worse the more I try. I've been using the default prusament PETG profile from the start and I keep the filament in a dryer set to 65°C. I would appreciate any assistance the community can offer.
RE: PETG Issues
As an update. My 28th print attempt was finally successful for the part, now it's time to begin the next one in the series. My problems today are even worse than yesterday with no settings changes. I believe I'm doing something wrong, but for the life of me can't figure out what it is. I continue to have odd print behavior as shown in the below image where the filament drags upward from the sheet. Once this begins, the print is doomed and it's only a matter of time before it begins to glob to the nozzle until it becomes nothing more than a mop. The first layer calibration prints slower with a lower nozzle temperature than the Prusament default settings, so I thought maybe that was the culprit. I created a copy of the Prusament filament and then adjusted the values to approximate the first layer calibration as closely as I can and it still fails exactly like shown below. I've checked my filament path to ensure there's no binding, I've confirmed the filament is crossing through the extruder gears correctly. I've tried adjusting the gear tension with the screw to no effect. I am running out of ideas. I've reached out to my local friends for assistance and get no help, they all warned me that buying a Prusa was a waste of money for outdated technology and the units can't print anything beyond PLA with consistent results. I want to prove them wrong, but my 12th failed print of the morning just occurred and they're looking more and more right as time goes on.
Do you have another print sheet - and have you tried the other side of your regular sheet?
Cheerio,
RE: PETG Issues
I have tried both sides of this sheet and even changed to a spare sheet. I continue to get the same inconsistent results each time. The only way I can get a print to be successful is if I pause multiple times on the first layer and remove the artifacts before the next line is placed. My current print involved probably 30 pauses to complete the first layer, it's definitely a different print experience to my first few hundred hours.
OK, let's try an extra rigorous washing: Rub neat dishwashing detergent (Dawn/Fairy) into the surface, leave it for a few minutes then rinse it clean with very HOT water, do not touch the surface but let it drain then finish the drying on the heatbed.
Any improvement?
Cheerio,
RE: PETG Issues
Anytime I have this issue with PETG it is because the textured sheet was not clean enough. The sheet may look clean but there are still oils on the sheet. Clean in while it is cooled down with 99% IPA and a clean paper towel.
RE: PETG Issues
I apologize for the late responses, I've been travelling for work and unable to try anything. I've now tried the deep cleaning with Dawn dish soap and it had no change. My first layer calibration continues to come out as near to perfect as can be, but the first layer during the actual print doesn't look anything like it. I even tried doing a print that matched the geometry of the first layer calibration and it still doesn't look good. Does the first layer calibration use different settings than the prusament profile? That's my only thought, there's some difference between them and that difference really matters for some reason.
RE: PETG Issues
try moving your extruder to say 60mm above the heatbed before heating for the next print. just in case you are suffering from thermal sensitivity with the pinda.
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: PETG Issues
I typically have it approximately 100mm from the print bed because I have to clean the filament blob from the nozzle the happen after the failure. That's the minimum distance I need to comfortably get underneath it.
RE: PETG Issues
fair enough.
do you use the inbuilt first layer calibration print to calibrate live Z?
have you tried using the first layer of a print, to adjust live Z?
it will probably work better than the built in print
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: PETG Issues
I use the inbuilt first layer calibration, but it doesn't ever seem to match the first layer of the actual print. I will try adjusting live Z and report back.
RE: PETG Issues
Good luck David.
I Find the inbuilt test unreliable...
so I either use a print with a flat first layer, or
"Life Adjust 'Z' My Way"
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
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: PETG Issues
I followed the steps in the link you provided and it seemed like it was helping. The images below are of what it looked like the left image being my first print and the right image is what I eventually got to. I've used calipers on the sheet and it measures between .2 and .23mm thick. I believe this is within an acceptable tolerance. Unfortunately, this hasn't helped my project succeed. I'm using the same settings on my project as were used for the calibration sheet and I've thoroughly cleaned the print sheet multiple times. Every print attempt I have ends up with filament gobbed up around the nozzle within 1 to 2 minutes of starting. I've attempted the print approximately 20 times with the same failure occurring at some point during the first layer. So my question now, does my calibration sheet look bad? Am I still out of tolerance? What should I do from here to make a first layer stick consistently?
RE: PETG Issues
the right hand print looks like it has ripples in the corners, this suggests that liveZ is a tiny bit too low (too large a negative number) it's close but not quite there...
Are you using 7x7 mesh bed levelling, or 3x3 mesh bed levelling.
I use 7x7 (available via the LCD Menu) and I use Magnet compensation, so the 7X7 tests 49 points on the build plate then the magnet compensation dumps 7 of these tests, so you get 42 points on your mesh bed levelling map as opposed to the 9 points, on 3x3 mesh bed levelling
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: PETG Issues
I was using 3x3, I wasn't aware it could be changed in the options. I've gone ahead and changed to 7x7 now. The magnet compensation was already on. You are correct, there is a small amount of waviness in the corners. The this is the region that came in at .23mm thick vs the smooth area that is .2mm thick. I will adjust the live-z up a small amount and re-try the print. I appreciate the help, getting this material dialed in has been a real challenge for me.
RE: PETG Issues
I wish you happy printing this weekend.
Best wishes, 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: PETG Issues
I remember having a difficult time getting my petg to stick to texture sheet the first time as well. but eventually it did after the scrub with dishsoap and sponge and then 99% IPA for good measure. About that time I switched to the satin sheet for all my petg and tpu printing.
the 75 or 100mm .2mm square is definitely the way to go so you have plenty of time to slowly lower the z to the point things start sticking.
I didn't see it mentioned here, but I have found that PETG, TPU and PLA all use different zOffsets. Once you figure out the right zOffset for the filament type, I'd recommend setting up steel sheet profiles:
https://help.prusa3d.com/article/steel-sheet-profiles_1955
You can name them for example: SmPLA for smooth+PLA, Tpetg for textured + petg, etc I think you can do 8 profiles in the MK3S+
NOTE: Remember to switch to the right plate profile before you print!
RE: PETG Issues
I've spent about 10 hours so far today and 12 hours yesterday trying to get this working and I'm no closer now than when I started. I believe the large square is a much better calibration method, but my unit is not consistent enough to be able to calibrate. I can print 10 squares in a row without a single adjustment and get 10 completely different squares. At this point, I'm willing to say my machine is not capable of printing consistently enough for this material to work. I suspect there might be a separate issue with underextrusion that is causing it, but I'm not willing to spend more than the approximate 40 hours I've already invested solely on troubleshooting this material. The inconsistency also explains why I will get a successful print that comes out perfectly and then fail the next 30 attempts. When I get the single time it's consistent, it works. The rest of the time, it's a blob of filament stuck to the nozzle.
The unit prints PLA and Nylon fantastic so I'll donate it to my robotics team and it will live a productive life there. Now I need to decide if the Mk4 or a Bambu is in my future as PET-G is my preferred filament for some work projects I have going on.
RE: PETG Issues
I wonder if if some things need tighen/adjustment. it seems like this is a symptom of some underlying problem. The only thing I usually have to do for petg, other than the steel sheet profile with the correct zOffset is usually bring the extrusion multiplier down. I'm doing some overture clear petg right now on my two MK3S+printers and the extrusion multiplier for this filament has to be .94 on one and .93 on the other. One has a brass nozzle and the other a hardened steel. If I go any higher than that for extrusion multiplier I get blobs.
RE: PETG Issues
That's a shame because I almost exclusively print PETG on my MK3S+ .. I use the rough/textured sheet. I wonder if your bed is a uneven. I have octoprint which has a bed level plugin and is good for seeing if you have some physical anomolies. If you notice your bed warped, I'd suggest something like the Silicon tube bed leveling. I have the stuff and just haven't gotten around to using it.. as my bed is not that bad. But I think the Prusa MK3 is likely one of the best PETG printing machines around.
I've spent about 10 hours so far today and 12 hours yesterday trying to get this working and I'm no closer now than when I started. I believe the large square is a much better calibration method, but my unit is not consistent enough to be able to calibrate. I can print 10 squares in a row without a single adjustment and get 10 completely different squares. At this point, I'm willing to say my machine is not capable of printing consistently enough for this material to work. I suspect there might be a separate issue with underextrusion that is causing it, but I'm not willing to spend more than the approximate 40 hours I've already invested solely on troubleshooting this material. The inconsistency also explains why I will get a successful print that comes out perfectly and then fail the next 30 attempts. When I get the single time it's consistent, it works. The rest of the time, it's a blob of filament stuck to the nozzle.
The unit prints PLA and Nylon fantastic so I'll donate it to my robotics team and it will live a productive life there. Now I need to decide if the Mk4 or a Bambu is in my future as PET-G is my preferred filament for some work projects I have going on.