Help me dial this PETG in...

[WobblyHand]

Coming back to this. I have been ignoring PETG, keeping it out of my mind. Until today. Now for the past month or so, I had the soggy red PETG in a vacuum bag with silica gel and partially evacuated. This apparently pulls absorbed moisture out of the PETG. Proof is in the pudding, as they say.

I did not change the base PETG settings in PrusaSlicer. I installed the "dried PETG" in my Prusa, sprayed my satin sheet with Aquamist unscented and cleaned the sheet. Aquamist apparently has dimethyl ether in it! Then dialed in the Z height and printed. No drama. Nothing bad happened. No crackling sounds in the extruder. As a matter of a fact, at the end, I just popped off the print. The vapors from the PETG are less than PLA, so that is good. I'm calling this a definite win.

This is an AXA lathe tool holder holder. It slides on 1.5" (38mm) 8020 (very snugly). The holders are held by the dovetail. There are minor issues with the print, but I am happy. PETG 0.3mm Draft, 20% grid infill. 4 line perimeters.

Same filament as before, just dried out under a partial vacuum. Well it's raining now, have to put the filament back in the bag... 30% RH in the house, 6% RH in the bag.

 

[jwmelvin]

That’s pretty great that it worked out. Mystery solved, apparently. I’ve definitely enjoyed PETG’s improved toughness over PLA.

 

[keeena]

I just my config/process for PETG in this post in case it helps: H-M Link

Are you using the PLA steel sheet for PETG?

 

[WobblyHand]

I am using the satin finish sheet for PETG and cleaning the surface with aquanet. Before aquanet, I had terrible release. I still have some petg stuck on one side (from previous attempts). This last time I did a light spray, wiped it off and then printed. Combined with dry filament, things came out ok.

 

[keeena]

When you say satin: you mean the smooth sheet correct?

Yes: releasing w/ the smooth sheet is going to be tough; I prefer the textured sheet and find it easier to deal with. It sticks well as long as Z is calibrated and using the right temps. And the PETG releases very easily once the bed cools a bit.

 

[WobblyHand]

When you say satin: you mean the smooth sheet correct?

Yes: releasing w/ the smooth sheet is going to be tough; I prefer the textured sheet and find it easier to deal with. It sticks well as long as Z is calibrated and using the right temps. And the PETG releases very easily once the bed cools a bit.

No. Prusa offers a smooth, a satin and a textured steel sheet. The satin and textured sheets are recommended for PETG, at least according to Prusa.

Except for me, at least with wet filament, I had over adhesion on the satin sheet. I pretty much ruined the middle of one side because I couldn't scrape off the PETG. I still have a now pinkish thin film of PETG there. Probably only a few thousandths, but it still doesn't want to come off.

I printed on a different location, and used Aquanet unscented hairspray on the surface. The first listed ingredient of Aquanet is dimethyl ether. In any case, I wiped it all over the surface and cleaned up the residue. The PETG did release when the bed cooled to about 40C. So that's what I will go with. That and vacuum bags with desiccant.

Edit: The lesson I learned is to treat all new spools as if they were wet. Just because the bag was sealed and vacuumed tight, did not mean the filament was dry. So from now on, I will rebag the new filament with desiccant, evacuate the bag and wait a bit. The evacuation/low pressure does help the filament to out gas, and the silica gel seems to capture the water vapor as long as one uses a lot of desiccant.

 

[keeena]

@WobblyHand - thanks for the clarification; I had no idea they came out with a Satin steel sheet and do not have any experience with it. I can see why they may have attempted a sheet in their lineup between smooth and textured...the textured can be too slippery for PETG w/o the proper tuning.

 

[7milesup]

@WobblyHand - thanks for the clarification; I had no idea they came out with a Satin steel sheet and do not have any experience with it. I can see why they may have attempted a sheet in their lineup between smooth and textured...the textured can be too slippery for PETG w/o the proper tuning.

I was rather shocked when I went from the smooth PEI sheet to the textured sheet in regard to PETG printing. It required a rather significant change in z-height tuning to get the PETG to stick.

 

[slodat]

I use the Prusa textured sheet with PETG. I have't cleaned it in months. I just print parts on it. They turn out great!

 

[weston1968]

@great white He is printing it vertically because when he prints the box (@WobblyHand's first post) they have to print vertically because of the walls of the box.
PETG is much more prone to stringing and blobs than PLA. Temp and retractions help with that. I have printed a lot of PETG with a 0.4 nozzle at a 0.2 layer height. Some of my prints turned out great, and some not so much. I found that brands of filament make a difference also. I recently tried to print some PETG from a new company that I was trying and had one heck of a time getting it to stick to the bed.
Your print shows a lot of ghosting. I am afraid I don't have an answer for that but an interweb search might help. Sorry about that.

I have tested many brands of PETG. PETG requires entirely different tuning than PLA and is less forgiving. It has a narrow range of print speed for any given flow rate and temperature. Too slow and the filament comes out of the nozzle to fast and you get blobbing. To fast and you get stringing and poor bonding. Too slow or fast will cause the PETG to wick up the nozzle and accumulate to the point it will drop onto the print. Hatchbox is the easiest to use PETG. Of the USA filaments Florida Filaments works the best but is nowhere comparable to Hatchbox. I consider myself successful when I get to the point that a 6 hour print job does not wick up enough to drop on the print. I clean the print head after every job.

Contrary to everything I have read, I have found there is no PETG manufacturer that makes a filament as strong as a good PLA+. The main advantage is temperature before distortion.

After not being satisfied with my finish the ability of my Robo R2's to meet my fussy finish requirements I built my own. My printers have zero play and large steppers with dual stepper Z drive and 4 posts on the bed and are designed for 24/7 operation. This has eliminated all of the variables except filament brand. The finish you get is very much limited by brand, even more than other settings.

The heavier the belts you use and the slower you print the less your ghosting. I think that ghosting is caused by sudden turning on and off of the filament flow being an impulse into the tuning of the carriage. Weight of the print head and the spring action of the belts is a nice oscillatory system.. The only thing that will eliminate ghosting is to get below the frequency of oscillation.