Ringing at certain Z-heights  

Re: Ringing at certain Z-heights

Hi Jacob,

Is this issue exactly at the same height on all your prints?
Do you have this issue since the beginning?

If the prints always finish without any issue except this, I would think maybe of a bad adhesion or some warping rising the print leading to a more squished layer at this precise moment.
Do you have this issue with all the filament?

The other possibility I can think of is a faulty wire from the extruder that leads to this issue when bent with the proper angle.

Re: Ringing at certain Z-heights

Yes, same height on all prints, as long as I've had the printer built.

This is my first ABS print, but I've had the same issue on PLA prints as well. I was worried about ABS warping, but I think the issue is separate?

If the issue is a faulty wire, think there is any way to narrow down which might be at fault?

Here is another photo of a different print with the same artifact. This one is a PLA print.

Re: Ringing at certain Z-heights

Can you show me your first layer?
It seems that your PLA part is not flat.

Re: Ringing at certain Z-heights

Unfortunately the PLA part was printed and mailed out to a family member months ago, so I don't have access to it anymore. This is the first layer of my ABS part printed yesterday though, you can see the bottom left corner where I was adjusting the live Z to get a better squish vs oversquished. It wasn't super attached when I took the print off, but I couldn't see any lifting either. I actually can see the ringing as it's printing, but as far as I can tell when I'm watching it print, it doesn't seem to be slowing down or hanging up on anything.

Re: Ringing at certain Z-heights

That's a not so bad 1st layer.
Do you hear any clicking noise when the printer prints this faulty layer?

Do you have the issue even with sample G-Codes from the SD card (or the samples installed with the driver)?
I think that would be the case, but it's always worth asking.

Re: Ringing at certain Z-heights

Only the clicking from the power supply, but I understand that normal. No clicking from the part or extruder hitting each other that I can tell.

TBH, I haven't tried the sample G-code since I got the printer, but I think the only think I tried was the prusa logo, and that might be thinner than the level where this issue occurs. So whoops, on my part there.

Thanks for your help btw,

Re: Ringing at certain Z-heights

Indeed, the Prusa logo must not be tall enough to see the issue.

Re: Ringing at certain Z-heights

Yes my MK3 developed this or something similar recently, it got worse and worse each print, as if it was getting less and less capable of pulling filament through, suggesting clog or something.

After complete teardown of the extruder assembly, the passive bondtech gear held to the trap door by bearing and shaft, was badly misaligned. This shaft had already worked its way out of one end of that part a month ago requiring a reprint of the part, and then hotglue on the end of the shaft (because it is simply too short to stay in place), and so I wasn't surprised to see this become a problem again.

I honestly don't know what to do about this other than trying to redesign the trap door part. Unfortunately the Teflon tube going into the extruder was damaged (during disassembly I assume), so my MK3 is now down for the count.

EDIT: OK so I'm still in chat with support, but this mystery is now solved for my MK3 thanks to support staff expert. Firstly, my original trap door part must have been defective and not restraining the shaft from slipping out. Second the replacement part I printed worked just fine until I started trying to print PET (higher temp) but since the repart was PLA, is gradually warped and shifted the shaft out of alignment.

SUMMARY: My 'ringing' artifacting was caused by misaligned bondtech idler gear twice, in both cases due to defective idler trap door.

The ringing artifacting I got was very consistent. On a small extrusion calibration tower, the ringing would basically appear every X layers.