Problems with PetG

[Bastian]

Hi all,

I have tried to print with PETG the other day and it was a complete fail. PLA works just fine but PETG has those spider webs and the quality of the print is poor, even tho' all settings are the same besides temp. I use 0.2mm layers, 240C and 60C for the bed. You guys have any idea why it makes those spider webs? I assume the PETG is too runny at 240C?

Thanks in advance for your help!

[Bastian]

Also do you see the difference in colour....it seems to change the shade of blue for some reason too?!

[Geoff]

Mayeb try slow down your printing, PETG on my printer needs to print rediculously slow, like 30ms feed rate :/ otherwise it gets lots of little air bubbles in it and goes stringy too.

[Alibert]

I think you should dry your PETG filament. It has a tendency to absorb a lot of water, which results in stream bubbles and also an increase in stringing.

[NitroXpress]

Hi,

230° is enough.
Print perimeters outside-in.
I have absolut no problems with stringing !

PETG is a much better material than PLA.
I only use PETG.
PETG does not absorb water !
I print PETG at 160mm/sec.
No need to slowdown the print.

High quality prints at 80mm/sec:

lizzard.jpg

[beerdart]

Try adding retraction. PETG is stringy stuff.

[Alibert]

PETG does not absorb water !

ALL filaments will absorb water to some level. Nylon is the most notorious one, but PETG also has its issues. As example, last Thursday I tried two PETG filament samples from Formfutura (received them in the post that same day). They came out totally messed up with steam bubbles when printed at 225 C. I have vacuum-dried them (70 C, 50-70 mbar for 8 hours) this weekend and will test them again coming Tuesday when I have time. I saved some of the extruded PETG with steam bubbles for taking pictures and comparison to give some feedback to Formfutura. I will post them here when I have them.

[Geoff]

Hi,

230° is enough.
Print perimeters outside-in.
I have absolut no problems with stringing !

PETG is a much better material than PLA.
I only use PETG.
PETG does not absorb water !
I print PETG at 160mm/sec.
No need to slowdown the print.

High quality prints at 80mm/sec:

lizzard.jpg

What printer?

I don't know of any of mine that can go faster than 50mms with PETG and give a decent result - you also are using White, try a transparent PETG, extrudes completely differently.

[Alibert]

PETG does not absorb water !

And here are the results of the PETG humidity test

I received a sample of the Formfutura Bronze PETG last Thursday and immediately tried it out the same day. When priming the extruder I noticed that the extruded filament (Flashforge Creator Dual, 225 C nozzle temperature, extruded using the display load filament feature) was very rough, indicating a LOT of absorbed water.

I vacuum dried the sample at 50 mbar / 70 Celsius for over 6 hours to get rid of the water. Today I repeated the extrusion, and made a comparison picture of the extruded filament of last Thursday (I save a bit) and today.

As can be seen, the sample as it arrived gave enormous amount of steam bubbles (bottom). After vacuum drying it is now extruded perfectly smooth (top).

Shame on Formfutura for sending out poor samples.

PETG_Bronze_Formfutura1.jpg

[dunginhawk]

nitro.. would you post your retraction settings?
I use PETG almost exclusively, but i dont have it perfect yet. I have a blob once in a while, but im 95% of the way there.
thanks