Creaking noise and blemishes after using new nozzle for a while
 
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James Ramsey
(@james-ramsey)
Active Member
Creaking noise and blemishes after using new nozzle for a while

I bought a second-hand Prusa MK3s, and the test prints with its original nozzle seemed fine. I then changed from the 0.4 mm nozzle to a 0.8 mm one. Initially, test prints seemed fine as well. When I started printing larger items though, I started running into problems, with "pockmarks" appearing on the surface, places where it looked like the line of extruded PLA had been interrupted before continuing. These pockmarks started appearing after a few inches worth of layers had been laid down. More worrisome were clicking and squeaking noises, and as I tried further interventions on my own--such as loosening up the idler door screw, cold pulls, and examining Bondtech gears--the noises when I did test prints, such as first layer re-calibrations, evolved into this grinding, creaking noise:

I'm not sure where to go from here.

Ce sujet a été modifié il y a 3 months 2 fois par James Ramsey
Publié : 29/06/2022 11:38 pm
Artur5
(@artur5)
Estimable Member
RE: Creaking noise and blemishes after using new nozzle for a while

Consider that a 0.8mm nozzle usually requires a much higher volume of extruded filament than the standard 0.4 nozzle.

I expect you use Prusa’s profile for a 0.8mm, nozzle but, even so, possibly you’re exceding the capacity of the hotend to melt filament at the rate demanded by that big nozzle ?. Hence the pock marks and other defects on the print. The grinding noises might be the extruder struggling to push non totally molten filament through the nozzle.

Please, provide us with more details about your printing settings.

Publié : 30/06/2022 10:36 am
James Ramsey
(@james-ramsey)
Active Member
Topic starter answered:
RE: Creaking noise and blemishes after using new nozzle for a while

 

Posted by: @artur5

I expect you use Prusa’s profile for a 0.8mm, nozzle

Yes. It's just the default "QUALITY" settings for a 0.8 mm nozzle in PrusaSlicer 2.4.2. Pretty much all the printer settings are defaults. The only change I made was the infill. Since I was printing what amounted to a 3 mm shell--a part of a helmet to be precise--I set the infill for that to 100%.

As I mentioned before, the pockmarks happened "after a few inches worth of layers had been laid down" on the helmet piece Here's what the piece looks like:

I'm not sure how clearly you can see the pockmarks in that image, so here are pictures of a side of a calibration cube before and after I started seeing the problems:

The gcode is the same for both cubes. Both were printed with a 0.8 mm nozzle. (Note that for the cube, I did not use 100% infill.)

Publié : 30/06/2022 12:07 pm
James Ramsey
(@james-ramsey)
Active Member
Topic starter answered:
RE: Creaking noise and blemishes after using new nozzle for a while

FYI, I tried putting white lithium grease on the Bondtech gears, and so far, that seems to have fixed both the creaking noise and the blemishes, at least in test prints. I've started a larger, more time-consuming print, so I'll see how well that apparent fix shakes out.

Publié : 30/06/2022 4:57 pm
James Ramsey
(@james-ramsey)
Active Member
Topic starter answered:
RE:

 

Posted by: @james-ramsey

I've started a larger, more time-consuming print, so I'll see how well that apparent fix shakes out.

Now that I've run several prints, it looks like the white lithium grease worked. I haven't seen any more pockmarks or heard any more creaks.

Indeed, I suspect that I may have unwittingly induced the problem in the first place by trying to fix noises that hadn't come from the extruder in the first place. I do currently sometimes hear clicks from the spool itself as the filament feeding right to the printer slips past the filament still wound on the spool. There are also some low squeaks coming occasionally from when the cardboard spool rubs against the spool holder--a holder that was broken when I got it and patched up by me with a dowel and some Steelstik and Worbla that I had on hand. Cardboard rubbing against the Worbla in particular seems to be the source of that noise. My guess is that I did myself no favors when I loosened the idler door, and my attempt to clean the Bondtech gears likely stripped them of lubrication.

Ce message a été modifié il y a 3 months par James Ramsey
Publié : 02/07/2022 11:08 pm
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