Surface adhesion with PETG
Hi,
I am using Prusament PETG on MK4S (0.6 non-HF nozzle) with satin sheet, and I seem to have some troubles with layer adhesion (I suppose).
1) After swapping the filament from PETG, first print I have always blob on the nozzle from the first layer not sticking. I immidiatelly clean it (remove and then metal brush) after that prints finished succesfully.
2) I had one case, where 1 of 12 same parts came loose halfway through the print. The 11 finished fine, with some embeded monster nest after the missing 12th...
3) I seem to have problem with lifting corners of larger parts. Like this one. At first, it was not too bad, but the cylindrical bit close to the bed was not very cylindrical...
I decided to fix it with adding brim tom improve the adhesion and the brim did this... And the bottom of the part is teribbly bowed. Rest came out as expected...
This is specifically Ultramarine Blue. I had much less problems with Signal White. I did not touch the settings in the PrusaSlicer. I clean the bed before print with IPA.
Any tips, how this could be improved one? I gotta say that I am a bit disappointed, since PETG is advertized as "easy to print" alongside to PLA...
0.6mm nozzles are especially sensitive to moisture in PETG and the blob is a typical symptom. With properly dried filament PETG really is easy to print.
The warping and some of the deformation are contributed to by poor adhesion. Give the print sheet a scrub with dishwashing detergent (Dawn/Fairy) and rinse clean with HOT water. Dab dry with a fresh paper towel and handle by the edges only.
If base distortion persists after this look at your elephant's foot setting.
Cheerio,
RE: Surface adhesion with PETG
Thanks. The strange is, that the blob is always just the first...
While some more attempts, I got this big bow of the base. I also realized, that for various reasons, I had this print not in the center of the print sheet. The room is relatively cold (20C), so I wonder if it could be due to an uneven print bed temperature?
Also the fill lines of the first layer are thinner than they were with other prints today... Seems similar issue as with the flimsy brim.
I that grid infill at a medium high density? Switch to cubic. It doesn't raise the filament at the crossings.
Cheerio,
RE: Surface adhesion with PETG
But this is bottom, both the bow the first layer. And the box is actually mostly empty shell so it does not have much internal structure. I checked, and the part which lifted is actually close to the edge of the build plate (the bow is on the right side):
You keep changing the part but not the problem.
Clean the print sheet.
Use cubic or gyroid infill to reduce pick up and blobbing.
And for the latest print, add a brim and ensure you are not printing in a draft.
Cheerio,
RE: Surface adhesion with PETG
Also that first layer is terrible, not enough squish there at all.
RE: Surface adhesion with PETG
Yes, the box is different from the first image, the last two is the same, just put it back on the bed for illustration.
I clean the bed, moved it to the centre of the bed, cleaned the nozzle. Much better, still a bit of lifting in the corners.
I'll be checking on the draft situation. I do walk in an out of the room occasionally and the hall is quite a bit colder; although the printer is opposite corner of the door. I also have air purifier close, exhaust pointed from the printer might not be enough...
For the squish (thank you for the term), what to do about that? I checked earlier prints, those look fine. There was nozzle swap in and out, but in the last batch of seems gradually worsening... I guess I double check nozzle mounting...
RE: Surface adhesion with PETG
I managed to get the prints quite good.
- I rechecked nozzle and heatblock mounting
- closed the doors and hold the... nature needs
- Turned off the purifier
- I preheated the bed for couple minutes
- I "change" the filament between each print. Before reinserting the filament, I rub the nozzle with the metal brush. After insertion, when the temperature drops to 170C, I yanked off the purge.
Worth noting, we have lower temperature outside (down to -10C, it was slightly above 0C before) and the house doesn't have much insulation. So even though the room is at 20C, the other parts of that can be down to 13-15C, and the printer is close to outside wall.
With the air purifier, as you might have guessed, the printer is in living room, I don't have much space. And from the research I did, PETG might shed some PM2.5 dust. So I got the purifier, and turn it on whenever PETG starts. If you are interested, I have IKEA FORNUFTIG, VINDSTRYKA for monitoring and controlling if using smart plug and Home Assistant.