PETG – Best printed vent closed?
I've had quite a lot trouble with my prints failing when printing PETG. One issue has been bed adhesion. Larger pieces detach during the print, smaller ones just end up being warped and wobbly. However I noticed, that when object was placed furher back, changes were better. I thought, that maybe it is draft causing issues. Now I have run several prints succesfully with the vent closed. Prints, which would have failed previously. And all that despite printer asking in almost every possible occasion, if the vent is open.
Have others witnessed similar behaviour?
RE: PETG – Best printed vent closed?
So far PETH prints have been fine on my Core One with the vents open. Chamber temps around 35C with bed temp of 85C.
RE: PETG – Best printed vent closed?
My PETG prints lifted at the edges too. It's a combination of the print sheet, bed temperature, ambient temperature, print fan speed and the chamber air flow from the chamber fans.
Closing the vent can help with warping, but might make overhangs difficult. Using a higher bed temperature or reducing the print fan speeds (or making it more dynamic) might do the same, but don't cause trouble with overhangs.
In any case, the default PETG profiles for Prusament PETG and generic PETG don't fully convince me. I only used the textured sheet though. Make smooth sheet + gluestick works better?
RE: PETG – Best printed vent closed?
I found that the textured steel sheet would have first layer issues when printing after the sheet had been used a fair bit. (Tried cleaning it with 100% ethanol, made no difference...)
I found that using an adhesive solved all of my issues with PETG. Honestly, I've been using Elegoo Rapid PETG and Prusa PETG without issues after that.
I've printed about 4 1KG spools at this point...
RE:
PETG shouldn't need high chamber temperatures to print without warping issues. Usually the satin plate is the best option, but with large objects, that might warp a bit, using adhesive fixes the possible issue in 99% of cases.
You might also print PETG on the smooth plate, but then it's compulsory to use a intermediate layer of adhesive (3Dlac, hairspray, Magigoo.. ) to avoid damaging the PEI sheet when you remove the print.
I never printed PETG on a textured plate, but expect worse adhesion and possible warping on the edges/corners of huge models. Yes, a layer of hairspray would prevent this problem, but it's best to use the satin plate instead of the textured.
RE: PETG – Best printed vent closed?
Satin plates are something, that I'll most likely try if I decide to keep the printer. All the current tries have been with a textured plate, as that seems to be the 'most recommended one' based on Prusa's web sites, although I've heard quite a bit for satin sheets since February when I placed my order. Messing with a separation layer is something, that I'm ready to do every now and then, but not for majority of prints. So I should find a solution for PETG printing that does not require it, as it is the material I most likely end up printing most.
Suprisingly my first layers have been pretty much perfect. Problems have only occurred later on, when either first layer has separated or suspected overextrusion has created a mess. Anyway, I'm not convinced on Prusa's own profiles either (despite using Prusament right now). I am starting to think, that people accusing Prusa for rushing have been right, as previously having thorougly tested profiles has been Prusa's strength.
Chamber temperatures haven't raised that high yet, and have stayed mostly between 30 and 40 degrees. So maybe that is something where 'beautiful Finnish summer climate' makes a difference.
Overhang performance is a good point, and it remains unseen. Now, I haven't had many overhangs, as I've printed tons of cable conduits (I need loads of them) and other objects on the 'flatter' side. Currently I am printing a model with more overhangs, so I know a bit more in two hours.
RE: PETG – Best printed vent closed?
Are you still using the brass nozzle? I found that the obsidian (sp) did better with not gunking up and messing up the prints.
RE: PETG – Best printed vent closed?
Are you still using the brass nozzle? I found that the obsidian (sp) did better with not gunking up and messing up the prints.
Yes I am. I've also heard the same, and some also say that non-HF nozzle would print better. At this point, I'm still wondering wheter these are just random noise in the data, or if investing on Obxidian nozzle would be worth it. Still, the printer in its stock configuration must be usable for me to even consider buying extra accessories.
RE: PETG – Best printed vent closed?
I've got them all... I'm using the HF .4mm now, I also have the .6mm HF and it prints great. Brass certainly needs to be cleaned...
RE: PETG – Best printed vent closed?
I've found the stock brass HF nozzle to ooze a bit, when printing slowly, but doing a great job when printing at high speeds with kinda low temperatures, which causes less warping, less stringing and usually a less shiny surface (which I like).
If you don't want to splash out for nozzles, print sheets etc. at the Prusa Shop yet:
I can recommend the Phaetus SiC nozzles. Got the 0.4 and 0.6, one from Prima3D in Denmark and one from the Phaetus shop on Aliexpress.
The Phaetus is better, when printing at lower speeds and if their hardness claims are true, very resistant to basically any filament (no CF/GF for me, until I got my DIY filtration ready though..).
The Obxidian nozzles claim to be better regarding PETG sticking to the nozzle, crawling up, but I didn't have that issue yet with either the brass HF or the Phaetus.
RE: PETG – Best printed vent closed?
I've found the stock brass HF nozzle to ooze a bit, when printing slowly, but doing a great job when printing at high speeds with kinda low temperatures, which causes less warping, less stringing and usually a less shiny surface (which I like).
If you don't want to splash out for nozzles, print sheets etc. at the Prusa Shop yet:
I can recommend the Phaetus SiC nozzles. Got the 0.4 and 0.6, one from Prima3D in Denmark and one from the Phaetus shop on Aliexpress.The Phaetus is better, when printing at lower speeds and if their hardness claims are true, very resistant to basically any filament (no CF/GF for me, until I got my DIY filtration ready though..).
The Obxidian nozzles claim to be better regarding PETG sticking to the nozzle, crawling up, but I didn't have that issue yet with either the brass HF or the Phaetus.
After one more day of printing, I am more confident with my conclusions. Core One can print PETG fine, but the recommendations default profiles are not that good. With vent closed I still had one print failure due to bed adhesion, but that was quite tricky print to begin with, and adding brim solved the issue. Filament build-up on the nozzle is definitely an issue, even when it doesn't ruin prints.
I'll add a satin plate to my next order. I think I should also do some testing of my own for PETG prints based on comments by Raaz. Lowering temps and increasing the speeds sounds quite good. I might also give Phaetus a try, as Obxidian HF 0.4 is out-of-stock at the moment on Prusa's webstore.