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herve.h
(@herve-h)
Active Member
PETG printing issues

Hi,

I just printed my 22mm OD 13mm ID tubes with Prusa PETG and SlicerPE PrusaPETG settings on my MK2.5, I have this :

Could I correct these "holes" ?

Thanks

Posted : 26/12/2018 8:45 pm
herve.h
(@herve-h)
Active Member
Topic starter answered:
Re: PETG printing issues

nobody knows ? :'(

Posted : 02/01/2019 9:02 pm
bobstro
(@bobstro)
Illustrious Member
Re: PETG printing issues


nobody knows ? :'(

It would help if you would at least describe the print settings you used. Layer height, extrusion width and speeds are important. Otherwise, we're just guessing.

Do you get the gaps if you slow down the print using the front panel knob while printing?

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 02/01/2019 9:17 pm
Nikolai
(@nikolai)
Noble Member
Re: PETG printing issues


Could I correct these "holes" ?

Print hotter (250C/255C) and slower. Make also sure your environment temp is not lower then 20C. PETG might warp like ABS under certain circumstances.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 11/01/2019 11:40 pm
Ledskof
(@ledskof)
Eminent Member
Re: PETG printing issues

I had a similar thing going on when I upgraded my 2s, and the problem wasn't settings. Slowing it way down made the problem less pronounced, but my problem wound up being a build issue with the extruder idler door. I found it when I started going through trying to calibrate my extruder steps. I found that when I told the machine to slowly extrude 100mm very slowly (following the guide here; https://mattshub.com/2017/04/19/extruder-calibration/ ) that the idler door would move out on the TOP RIGHT (where the hinge screw is!) every so often. Somehow, and the part isn't broken - I still have it - the whole thing was jacked up.

I had printed two sets of parts to do the upgrade, just in case. I broke the first idler door because the shaft holder pin holes are so tight. So I overcompensated on the second one and made it too loose. What had happened is that one side of the idler gear pin had slid away from the mount ear. I managed to get the printer to make another one by gently moving that back into place and printing it very slowly. I then was more careful leaving plenty of friction to hold the pin but not enough material that it was break the part, and rebuilt the idler. All my issues went away.

Prior to this, I was struggling to find a idler tension that would work. I had lots of gear noise, grinding, clicking, squeaking... and when a print would start the pressure equalizing line at the very start of the print would come out as sort of a wavy line. Evidently it would get thinner as the extruder gears were sliding past each other on the very end, not driving the filament. After finding this issue with the idler door, I was able to set the tension exactly as described in the assembly instructions, and haven't had an issue since that time.

Another symptom of my problem was that infill was weak. There were gaps in it. I had less issues with exterior walls, probably because those get printed slower anyway, but there were issues there as well.

I've printed two more extra emergency idler doors just in case this one I printed while extrusion was uncertain wind up cracking or something due to weakness, but so far it seems just fine. 🙂

I know one fix doesn't mean every problem is dead, but I believe the idler door assembly is a weak spot for these printers due to the extremely short shaft you have to work with, and due to the tolerance of the hole and how they designed it to be held in place. I really hope the information helps you find your issue!

Posted : 19/01/2019 11:52 am
Ledskof
(@ledskof)
Eminent Member
Re: PETG printing issues

BTW - the MAIN reason I posted this was that strangely, the issues I was having only showed up while printing PETG. It never showed up printing PLA. Those prints always came out looking great. Go figure!

Posted : 19/01/2019 11:53 am
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