Did your transparent print didn’t look transparent?
The PETG I am using here dislike beeing hot for a longer time within the nozzle. So the most transparent result (3rd from left) was obtained with 300% Multiplikator, clearly showing that my mechanical system could not bear this and produces “wobbles” due to vibrancy.
With lower temp. and just a bit higher speed i got the one on the left which is ok so far.
So I can not print fast enough for the temperature i need!
I wasn’t aware that slow printing keeps the plastic hot for too long so it start to degas or whatever - can anyone explain this?
[edit] using a pre-dehydrated filament solved the issues - so it was moisture!
@Jan_erik_Halvorsen yes I remember this wonderful glas like objects, maybe also the big nozzle/layer led to a very short “hot time” as you print lots of mm³ per time.
PETG likes layers to be as thick as possible. Try layer thickness at 80% of nozzle orifice. It’s a slightly separate issue, but you might have moisture in the material there, if you see puffs or bubbles in the material as you extrude it.
@Jeff_Parish you need cooling for PETG anyway and i would wonder if more cooling would help as the fillament leaves the nozzle already opaque when printed “slow” (70mm/s and below) as @Jeff_DeMaagd noted, i also thought about moisture but it was a sealed spool (which will say nothing) but I thought that moisture will puff always and not only if heated to long … we are 100°C above the phasechange so i could not belive water will stay bound in while the plastic is molten - but maybe - maybe if it is only a little moist! Maybe the pressure while printing faster play a role?
Where would the water go? You’re heating it in a metal barrel / block. The material forms a “cap” up top so much of it has to go out the nozzle with the plastic. Embedded steam can bubble out of your extrusion beads. I’ve seen it happen on one of my PETG spools and the problem went away after I dried the spool.
And water in heated PETG will degrade the polymer through a process called pyrolysis, reducing the strength of the material. So another reason to consider maybe it’s worth trying to dry it.
I’ll give it a try for sure!
But what i ment was, that if water is in - doesn’t this would cause problems independently from the extrusion speed? I wonder as i could extrude this proper(fast) – could a moist filament be extruded proper under certain conditions? Didn’t water would bubble out after leaving the nozzle? At least i would expect that this would be worse at high extrusion speeds and not vanish. - let’t see if drying helps!
