Issues printing PETG
When I print PETG often strange things are happening:
It looks like that sometimes it pushes too much filament through the nozzle which then creates a bubble around the nozzle.
If that happens, then I have to abort else the nozzle crashes into those hard PETG blobs.
- The belt tension is correct.
- The filament is dry (10% humidity).
Best Answer by cryptomilk:
What slicer do you use? If you use a Prusa slicer, you just choose the right printer profile, filament, layer height and quality, you don't usually have to worry about anything else. Especially if you are new to 3D printing, there is no need to change the profile settings.
Obviously I do. As the default profile for Prusa Slicer doesn't work flawlessly with Prusament PETG. I've printed gridfinity bins and tuned the Prusament PETG Profile till I didn't have any Filament collecting as a blob at the Nozzle anymore. I first tried with 0.99 and then started to lower it by 0.001 till I found the sweet spot. Then the filament which the nozzle collected was really low. I then raised the fan speed by 1% and I get really good prints now.
Prusament PETG (Pimped)
Extrusion Multiplier: 0.986
Fan Speed: 31%
You can print Prusament PETG Orange and Black with the speed profile. You can't print the colors Chalky Blue and Pistachio Green with speed profile, only structural works!
RE: Issues printing PETG
Ok, in the Filament tab for Prusament PETG, I lowered the value for Max volumetric speed from 24 mm³/s to 23. That seems to help. Will try with 22 mm³/s next.
RE:
I'm new to 3D printing and have to learn things. I searched the forums for help with PETG. Then I started to play around with the Filament settings. Looks like I figured it out.
If you print PETG and the filament collects as a blob around the nozzle you should do the following:
Filament:
* Extrusion multiplier: 0.99
Cooling:
* Fan Speed Min: 35%
With these two changes to the Prusament PETG my nozzle is clean during the whole print.
RE:
Or not, now the layers don't stick to each other. Maybe 0.995 ...
RE: Issues printing PETG
For strong petg parts you want as little cooling as you can get away with, petg needs temperature to melt into the previous layer, increasing the fan speed will give better looking prints but much weaker layer adhesion.
Try increasing the temperature but watch out for stringing and bridging issues.
I also find that a good petg print is glossy, a too cool print has a Matt finish.
Small test prints with a pointy part and bridging sections can help dial in petg and use the structural profile in slicer to I am finding the speed profile is pushing it a bit too much, it works for some prints but not all, it depends on the print.
Normal people believe that if it is not broke, do not fix it. Engineers believe that if it is not broke, it does not have enough features yet.
RE: Issues printing PETG
Thank you very much for the explanations!
RE: Issues printing PETG
What slicer do you use? If you use a Prusa slicer, you just choose the right printer profile, filament, layer height and quality, you don't usually have to worry about anything else. Especially if you are new to 3D printing, there is no need to change the profile settings.
I am from the Czech Republic, I don't speak English, I translate using Google Translate
RE: Issues printing PETG
I have seen similar issues on prints that print on speed profile and include long stretches of infill like the one below, I never saw this happen but it did happen twice in a row. I checked belts suspecting it was skipping on long fast infill passes, and yes, min where loose. Third time I switched to gyriod infill to avoid the long fast passes and it printed fine.
I am new to this and have taken the approach to tweak as little as possible initially, I simply got myself a stack of Prusa filament and use the default profiles. The things I change is perimeter and infill. I will eventually tweak things because I know I will not be able to keep myself from doing that, but I force myself to start simple.
one other thing I did do after these problems is to switch to a 0.6 mm nozzle, subjectively it seems to print better and I can use speed profiles with any infill without problems like these.
/Anders
RE: Issues printing PETG
What slicer do you use? If you use a Prusa slicer, you just choose the right printer profile, filament, layer height and quality, you don't usually have to worry about anything else. Especially if you are new to 3D printing, there is no need to change the profile settings.
Obviously I do. As the default profile for Prusa Slicer doesn't work flawlessly with Prusament PETG. I've printed gridfinity bins and tuned the Prusament PETG Profile till I didn't have any Filament collecting as a blob at the Nozzle anymore. I first tried with 0.99 and then started to lower it by 0.001 till I found the sweet spot. Then the filament which the nozzle collected was really low. I then raised the fan speed by 1% and I get really good prints now.
Prusament PETG (Pimped)
Extrusion Multiplier: 0.986
Fan Speed: 31%
You can print Prusament PETG Orange and Black with the speed profile. You can't print the colors Chalky Blue and Pistachio Green with speed profile, only structural works!
RE: Issues printing PETG
I have seen similar issues on prints that print on speed profile and include long stretches of infill like the one below, I never saw this happen but it did happen twice in a row.
There seems to be filament you can't print with the speed profile. See my post above.
I ran into similar issues. If you get a blob at the nozzle and it drops on the model you have a hard structrure sticking out. If the print head runs into this, it could dislocate and then the print is totally off. Do a structural print, check if filament forms a blob around the nozzle, if this is the case tune like I described in the previous post.
RE: Issues printing PETG
I have seen similar issues on prints that print on speed profile and include long stretches of infill like the one below, I never saw this happen but it did happen twice in a row.
There seems to be filament you can't print with the speed profile. See my post above.
I ran into similar issues. If you get a blob at the nozzle and it drops on the model you have a hard structrure sticking out. If the print head runs into this, it could dislocate and then the print is totally off. Do a structural print, check if filament forms a blob around the nozzle, if this is the case tune like I described in the previous post.
If I get blobs or much stringing then yes, my prints fail, but to be honest I had 4 such failures. First two was petg 0.4mm nozzle before adjusting the belts. Third was due to my own silliness playing with support structures that did not stick to the bed resulting in a small birds nest and the last was a pla print where a small object got knocked of the plate making a mess of 5 out of 50 copies on the plate. The two last fails did not produce layer shifts.
I would not say you can’t print petg using speed profiles, I mostly use speed profiles with petg and a 0.6 nozzle now using structural only when I think I need it.
I forgot to mention one thing. When I had the first layer shifts my printer was flat on my woodworking bench which is a several hundred kg beast, that meant that the stepper motors had to take all the strain of acceleration and deceleration and that is what I think contributed to my failures, your case may be different. Since then I moved the printer to a stack of heavy ceramic floor times with soundproofing material in different thickness between plates. This means that the printer can wobble a bit on acceleration and deceleration and it seems to print better, subjectively. I have not had a single layer shift since I moved the printer to that dampening stack. That is an ongoing experiment mostly driven by wanting to move the printer off my woodworking bench to its designated place which is far less stable, it just seems to have nice side effects.
/Anders
RE: Issues printing PETG
I don't have any issues with Fiberology PETG. It is just Prusament ...