PetG trouble  

RE: PetG trouble

Hi,

make sure the filament is dry. Otherwise it's futile. 

Then, check the "speed" view in Prusa slicer. The printer is coming from a slow section, then speeds up and something happens. The question is, why.

Check the filament path whether it moves freely or gets stuck in the PTFE tubes, then snaps loose.

You may be able to fix the symptoms by generally reducing print speed but of course that's just a hack not a solution.

I'd also do a cold pull, check the outside of the nozzle and the extruders (open idler, is there debris inside, is the wheel clean?)

RE: PetG trouble

Did retightening of the belt after adjusting it using the Vernier Skew Testing tool downloaded at printables a few days ago. Since Skew calibration, print results where bad at best. Additionally I but the my PetG into my polydryer. 

First print with PLA looks promising, will start PetG tomorrow 

Do 

RE: PetG trouble

had similar problems. nozzle was loose and optimized x-y belt tension.

can you post your profiles? - my prusa-slicer does not have a "PETG" Printing Profile!?

uploaded my current print and filament settings and would like to hear feedback 😉

slowed down some infill speed settings (best settings from 0.2mm Structual profile)

https://github.com/josy1024/GCodePlayground/tree/main/PrusaSlicer

RE: PetG trouble

Now the PetG results are in.

Same model just changed from PRUSAment PLA to PRUSAment PET-G and troubles are obvious picture

Interestingly there is on line of layer shift and then forward the area of the seam is problematic and quite awfull to look at

Must confess I don't know what's the Problem 

Help would be needed

RE: PetG trouble

After some reslicing and other tempering I tried changing slicing profile from 0,2 balanced to structural and wow, result changed considerably 

RE:

Posted by: @docsascha

After some reslicing and other tempering I tried changing slicing profile from 0,2 balanced to structural and wow, result changed considerably 

 

That's a reduction in speed - fixes the symptoms (better than nothing) but it would be better to understand the root cause. Try a "speed" profile to provoke the failure mode, or crank up the dial on the printer to 300.

BTW, I think the best indicator is "actual volumetric flow rate" in the slicer. My bet is that problems will show in high-rate areas, when entering from slow sections.

RE: PetG trouble

Thank you for the answer, your right print time increases +70 minutes

I not quite understand how to "Try a "speed" profile to provoke the failure mode, or crank up the dial on the printer to 300."

Sascha

RE: PetG trouble

As I looked at the print using the structural setting, quality improved but still there are some serious issues with the result. 

RE: PetG trouble

Just Use my petg profile from github. Ive lowered some speeds values < 100.

https://github.com/josy1024/GCodePlayground/tree/main/PrusaSlicer

You Can also retry printing a "petg Temperature tower" , maybe increaseing temp +5 or +10 °C for Filament settings helps too.

(I sometimes change nozzle Temperature during printing to immediately see impact) 

Also tweak with cooling of filament settings. 

Eg: min 20% max 50%O

Maybe too much cooling in overhangs? 

(I do not See any typical petg stinging so I assume you Can Print with higher temp to improve) 

RE: PetG trouble

Posted by: @docsascha

Thank you for the answer, your right print time increases +70 minutes

I not quite understand how to "Try a "speed" profile to provoke the failure mode, or crank up the dial on the printer to 300."

Sascha

Hi,

from what you've shown I'm suspecting the printer fails when the material is flowing too rapidly (in mm³/second, aka "volumetric flow"), maybe because of a partially clogged or damaged nozzle.

For debugging, you can provoke this failure by turning up the speed dial to 300 %, which more or less maximizes this "volumetric flow" to the maximum the printer can sustain - or thinks it can with a good nozzle. If it works at (or below) 100 % speed but falls apart at 300 %, you have narrowed down the problem. 

RE: PetG trouble

thank you for the answers I will test it and be back with my findings

RE: PetG trouble

If it doesn't go away, order a spare nozzle. Always good to have the option, if only to rule out nozzle problems. 

RE: PetG trouble

Hi, 

Results are in but I can only share one picture within this post 

Looks like 300mm does not work with this Obxidian HF nozzle. 

I will change to a new brass HF nozzle and try again

RE:

Results are in but I can only share one picture within this post 

If you want to post more results with the brass nozzle, you can upload more than one picture here:

RE: PetG trouble

Hi, 

changed the Nozzle, did it again with 300%and except for infill printing problems quality seems OK for this crazy speed setting

So the OBXIDIAN Nozzle seemed the problem, will order a new one rather 0,6 than 0,4. 

Will print some abrasive Material in the next weeks, should I go for HF or Standard Nozzle with abrasive Material

RE:

A bit surprised that the infill falls apart so badly but maybe it's a case I haven't tried. Corners blurring and walls getting slightly wavy (and general loss of adhesion - part breaks easier) is what I'd expect. Anyway.

For an opinion: Unless you have a reason for HF nozzle, that is, you need higher volumetric max. throughput (which usually translates into a smaller speed advantage than we'd like), get a regular nozzle. Avoid the additional complexity e.g. risk of one channel clogging up.

When you have it sorted out, practice "cold pull" procedure with the expensive problematic nozzle, most likely you'll get it back into shape. It takes some patience to establish the "process", plan to spend an hour or two with the printer - not rocket science but maybe a bit like "cooking".

Speaking of expensive, some cleaning filament might be a good investment for the cold pull (but regular PLA is also pretty good, amazingly sticky).

RE: PetG trouble

For an opinion: Unless you have a reason for HF nozzle, that is, you need higher volumetric max. throughput (

Have you tried OrcaSlicer?

It offers great options for determining the maximum flow rate, for example, if you really want to take advantage of HF.

RE: PetG trouble

Hi, 

Thanks a lot, infill pattern problem gratulty increased and I stopped the print.

Will not buy HF nozzle for abrasive Material, and stick with brass one at the moment

ORCA slicer, still didn't try but will do shortly 

Sascha