Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
I've been trying to print in PETG for the last two years, have gone through several kg of filament, and feel like I've tried just about everything imaginable. and while I have had "successful prints" none of them where acceptable quality. I've read countless Reddit subs, Prusa forum posts, read articles, and watched YouTube videos with all kinds of tips, but nothing has the slightest effect on the quality of the prints. I can print PLA without the slightest issue, but PLA is almost completely useless to me. I'm about ready to throw my Mk3S+ in the dumpster. Can someone walk me through what I need to do to make this piece of **** produce a usable 3D print? Currently trying to print a Dummy 13 as a gift. With the same g-code it will sometimes produce a blob of doom, sometimes spaghetti, sometimes start clicking part way through and clog.
Preparation and setup information:
- Currently use a tungsten carbide nozzle (3DMaker)
- Ventilated enclosure (MakerGadgets Professor)
- Z offset -2.4
- Textured PEI bed
- Clean the bed between uses
- Dry the filament (55C, for several hours)
- Infill increased to 20%, with honeycomb pattern
I can't attach the .3mf file as far as I can tell, so here are screenshots of where all my settings vary from the default (default on the right)
RE:
I would dry the filament at a higher temperature (over 60 °C) for at least 4 hours. For PETG on my MK3S+ I use the settings in this screenshot, click on it to see it without cropping.
I have the same settings for this filament for printing it on my MK4 with IS. Both printers print PETG without problems. Also maybe the tungsten carbide nozzle needs a higher temperature? I know this is needed for hardened steel nozzles other than ObXidian ones, not sure about tungsten carbide nozzles.
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
Thank you for your response! I'll give those filament changes a try, one at a time. I'm guessing the higher temperatures for the steel nozzles is due to their thermal conductivity being much worse than brass. Tungsten carbide is very close to brass, from what I understand, so it shouldn't need significantly higher temperature if I understand it correctly.
I'll report back with the results.
RE:
I hesitate to try the temperature you recommend because I am already having issues with what appears to be too high of a temperature. The features that I noted with arrows are supposed to be spherical. This is the Dummy 13 file I linked to above, with the settings I showed. There is also pretty egregious stringing, which I attribute to temperature as well.
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
Update: I gave it another go with even more drying, and the 1.02 extrusion multiplier. It came out basically the same, but less extreme.
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
Are you sure you are using a 0.4 mm nozzle? This looks like something bigger. The layers look a bit wobbly. Is there anything loose in the motion system of your printer?
As it happens, I have a print of the same part that I printed some weeks ago on my MK4 with the same temp settings for PETG as in the screenshot in my last post and the printer settings in the screenshot below (0.4 mm ObXidian nozzle, 0.15 mm Structural). The filament is eSun PETG black. I always print PETG at these temperature settings. I have compared prints made with the 0.15 Quality setting on my MK3S+ and the difference to the ones from my MK4 is very little.
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
Please forget my remark about the nozzle size on your print. I just saw that my print was scaled to 150 percent. No wonder if the layers on your print look relatively so much bigger then. 🙂
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
Thanks again for replying. I am using Inland PETG+, which is made by eSun. eSun doesn't sell a PETG+ on their website, so I'm not sure if it is their PETG+HS, or what exactly is different about it vs the regular PETG, but it is definitely shinier. I'm posting the difference between my current settings and the Prusament preset for reference.
I bumped up the maximum cooling to 35% and ran it again. I stopped it early because parts had already detached after a couple of layers. The print shows some other concerning bits, though. There are raised bumpy areas all over. I've circled the largest offender. There is also bits of grey filament from when I did a swap in between prints.
RE:
As this was on my to-print-list anyway I printed the part again, this time without changes in scale and on my MK3S+. This is the result. Still bit of stringing on the upper layers, but this is to be expected. But the important thing is that the spherical parts are round and the straight edges are straight with no stepping/wobbling between the layers.
A few seconds with a hot air gun took care of the stringing:
I have also attached my project file from PrusaSlicer.
RE: Can't Print PETG - curling edges, blobs of doom, burnt blobs, clicking feeder, nozzle clogs
I ran gcode generated from your 3mf file, and it came out much better, but still has some issues. The overhangs are still very poor. Overhangs curl pretty badly, and that may be causing them to be just misshapen in general. Spheres are still a little conical, but the joints actually function now. When printed in lighter colors burnt blobs become visible as well. Top surfaces are rough, and have gaps in the infill. I also looked into the ringing I've been getting, and found that the belt self test checked out, but when I ran the audio test on the Prusa app it didn't even register. They were far too loose, and I had to shorten the x axis belt to get it to tighten up properly.
Sagging overhangs, rough tops (on the pinky):
Burnt blobs clearly visible, gaps in top fill, poor overhangs:
Poor overhangs, ringing:
