What are these ripples along flat sides?  

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Ira S
(@ira-s)
Trusted Member

I have a MK3, a couple of years old, and it prints wonderfully. But no matter what I print, I see this pattern on the flat sides of things. I know it's nit picking, but still I'd like to know why.  As far as I can tell, the ripples are about 0.6mm center to center. It happens on both the X and Y sides of a square object.

 

This print was with layer height 0f 0.1mm, but layer height doesn't matter. What's also interesting is that they ripples line up from layer to layer.  The print was sliced with PrusaSlicer, with 2 perimeters. This is Prusament PLA. 

 

It's not ringing, because it is all long the side, not just at corners or changes in a side. The printer actually doesn't show much ringing anyway. 

 

Can anyone tell me what's causing this and how to eliminate it? Thanks. 

Y Side

X Side

Posted : 18/03/2021 8:31 pm
Neophyl
(@neophyl)
Famed Member

They are called vertical fine artifacts.  You can learn all about them in this thread https://forum.prusaprinters.org/forum/original-prusa-i3-mk3s-mk3-user-mods-octoprint-enclosures-nozzles-.../stepper-motor-upgrades-to-eliminate-vfa-s-vertical-fine-artifacts/   which is 50 pages long.

Posted : 18/03/2021 9:04 pm
Dan Rogers
(@dan-rogers)
Honorable Member

@neophyl

I read that article and even ordered (and have) the "drop in replacement" stepper motors that apparently I will just need to handle the wiring for to get rid of these little lines.  It's interesting that they look to be spaced exactly the same as the belt notches .... but that's probably a coincidence.   I haven't torn things down to install them yet - was hoping to find someone that was ahead of me and verified that after all of that work, the improvement is noticeable.

In the mean time, getting rid of those marks when it matters just takes a little bit of sand paper and elbow grease.

Posted : 18/03/2021 9:08 pm
Ira S
(@ira-s)
Trusted Member

@neophyl

Thank you, this definitely explains it. Interesting article. Based on the work involved, I'm going to live with the VFA. 

@dan-rogers

I'm not sure that the artifacts actually match up with the belt notches, even counting raised and lower portions. I believe the artifacts are a little closer spaced than that, but would need a better magnifier than I have to be sure. 

Yes, sandpaper and elbow grease for the few times it matters. 

 

Thanks. 

 

Posted : 18/03/2021 10:11 pm
Dan Rogers
(@dan-rogers)
Honorable Member

Note - those VFA's can be "blurred" by de-tuning your belt a little - that you are seeing them says you did a good job with lubrication, alignment and belt tension.

Posted : 19/03/2021 3:22 am
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