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Extruder clicking during retraction  

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claude.a3
(@claude-a3)
New Member
Extruder clicking during retraction

Hello,
while printing the brim or the first layer my extruder makes a clicking sound while retracting. This also causes gaps in the filament.
I can clearly see the filament retracting out of the extruder and then see the gap in the filament being laid down. This hapens on straight lines.
When the printer is extruding normally the filament is laid down perfectly.
What is causing the extruder to retract on a straight line?
I am using slc3r to slice the objet created with OpenScad. The printer has the latest firmware.

Thanks in advance for your support.

Claude

Veröffentlicht : 09/02/2019 7:41 pm
bobstro
(@bobstro)
Illustrious Member
Re: Extruder clicking during retraction

Are you sure it's retracting and not just skipping? I wouldn't expect retraction on straight lines, but that is where you'd get skips as the printer comes up to speed. Easy test is to dial speeds back with the front knob. Dial it back 50%. If it helps, that will give some hints. Pics will help as well. A summary of material and settings as well.

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

Veröffentlicht : 09/02/2019 8:18 pm
claude.a3
(@claude-a3)
New Member
Themenstarter answered:
Re: Extruder clicking during retraction

Thanks for the quick response.
Settings in slic3r 0.2mm FAST MK3, I tried Cura, same problem.
Filamant is PETG, same results with 215C or 250C hotend temp.
I created a rectagle, 0.8mm thick so I can watch the print and adjust the z offset since I originally speculated that was the issue.
In the pic you can see gaps, the filament is deposited countinouisly then there is a gap and the extruder restarts to deposit with some dificulty.
There are gaps front and back, always in the same areas.
My filament is in a humidity controlled box with a boden tube that feed it directly to the extruder input. ( less contamination but not completely scealed up to the extruded). When the extruder retracts, the filament and the boden tube move away from the extruder input. When the filament is feed into the extruder the boden tube is flush against the extrude input. There is no question, the clicking is during a retraction.

Veröffentlicht : 09/02/2019 9:51 pm
bobstro
(@bobstro)
Illustrious Member
Re: Extruder clicking during retraction

That's not where I'd expect retraction. Check in slicer preview to confirm retractions are happening there. Have you checked for a partial clog? A cold pull might help. Not sure why it'd be limited to your 1st layer.

You might try feeding some filament externally to verify it's not a feed path issue.

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

Veröffentlicht : 09/02/2019 10:04 pm
claude.a3
(@claude-a3)
New Member
Themenstarter answered:
Re: Extruder clicking during retraction

I think you may be right. If there is a clog, it could be possiple the pressure builds up compressing the liquid filament wich then acts like a spring pushing back the hard filament and causing it so slip over the extruder teeth.

I will try a cold pull.
Thanks

Veröffentlicht : 10/02/2019 4:55 pm
claude.a3
(@claude-a3)
New Member
Themenstarter answered:
Re: Extruder clicking during retraction

Found the problem: partially clogged nozzle.
I tried multiple cold pulls without success.
Finally I replaced the nozzle. Prints are perfect now.

The retraction was in fact the filament slipping on the extruder gears.
Best way to diagnose this problem: unload the filament and reload it. If the extruder clicks during loading and too little filament is exiting the nozzle it is a partial clog.

Keep replacements nozzle on hand, they are not very expensive.

Thanks for the help.

Claude

Veröffentlicht : 10/02/2019 7:50 pm
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