Z wobble or what?

Ender 3V2, sort of.

I had a print, 1/2" x 4" x4" hollow box, that had the dreaded small wavy lines on the long side but the narrow end sides where fine. I have, about the same time, also printed other models, flat sided, without any of those artifacts. Is there some reason that I am getting this but only on some models and not the others or only on parts of the model

Is it the shape of the model or some deficiency in the printer. Maybe something else?


Thank you for reaching out.
The issue you’re encountering, with small wavy lines appearing on the long sides of a hollow box print while the narrow ends remain unaffected, could be attributed to several factors.
For instance, variations in Z-offset, bed leveling, or filament flow could contribute to these artifacts. Since you mentioned successfully printing other models without similar issues, it’s plausible that these factors may be interacting differently depending on the specific geometry and layout of the model being printed.

If you can provide some photos of your defective models, I may be able to answer your question more specifically.

Best regards, Alex

This can be a ton of things. I am assuming it is not related to first layer issues you have been around long enough to see these. I would suggest its related to the stepper, VFA… Vertical Fine Artifacts. YUCK. Article that has a picture of what it looks like.

It could be vibration generated by movements and long or short will change them depending.

It could help to try a few tests to see what if effecting the issue.

Print a print with that issue again, ½ the speed. Try changing the orientation by 90º different layer heights.

These will change the variations and might lend insight to where the issue lays.

That seems to be what I had happen. I will try and post a pic but the detail may not show up.

This is a pic of a printed part and it does look like VFA’s.

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OK, Just for $#!+$ and giggles I backed the tension on the offending Y axis belt off some and it did help quite a bit, not all of it but enough to show it is the right direction. The VFA’s seemed to be reduce well over half.

You don’t want to back the tension off too much otherwise you may run into the opposite problem.

VFA’s are unfortunately normal and expected on 3V2’s so while backing off your belt tension does get rid of them you will start to introduce more slop and dimensional inaccuracy into your parts.

There are ways of tuning your belts to the exact tension they should be, you can find what frequency the belts should resonate at and then use apps on your phone (or the more fancy technology if that is available to you) to measure the frequency when you pluck the belts like a guitar string. You can then ‘tune’ the belts by adjusting the tension on the belt until it matches the desired frequency.

From a quick google search it seems like you are looking for around 94Hz on the X-axis and 113Hz on the Y-axis: Benchtop Machine Shop: Printer: Belt Tension

I always hate tuning my belt tension, it is so tedious and boring. But it is definitely worth it in the end!


Found that out the hard way. I back them off so far that while the VFA’s disappeared for the most part the layers looked like they where not lined up (all sloppy like) like they should. I am adjust the belts a little at a time to see I f I can hit the sweet spot or as close as I can. It may tale a few years.

For sure they look like VFA to me. Fiddling with belt tension can help a bit there is likely a sweet spot between too loose and too many VFA. Speed will change them as will layer heights and surface shapes. They will not really go away however, different steppers are likely the only real fix.

Did you check the iddler pulley? They are smooth pulleys but should be teeth pulleys so the belt’s teeth can fit in them, preventing more VFAs. On the smooth pulleys, the belt’s teeth will produce vibrations. You can check if the VFA wavelength has the same pitch as the GT2 belt pitch.

These pulleys have teeth.

I didn’t have this problem before a couple weeks ago, that is what is perplexing.

What is the pitch of this VFA? It may give some clues.

1 mm to 1.5mm pitch.