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I've printed a 2x2x2 cm test cube with Slic3r (left) and Ultimaker Cura (right) and my Prusa i3 derivative machine with tight belts. The print settings should be quite equal (0.15 mm layer height, 40 mm/s outer wall speed, default accelerations/jerks). Though the top surface of the Ultimaker Cura-cube looks much better than the Slic3r-cube,

Left: Slic3er, right: Ultimaker Cura

the latter has much flatter vertical walls than the first.

Left: Slic3er, right: Ultimaker Cura Left: Slic3er, right: Ultimaker Cura

The front wall of the Ultimaker Cura-cube was printed from left to right which could explain the wavy result as some kind of vibration caused by the sharp y-stop at the left front corner.

But what setting could have influenced this? Should I try to manual setting of lower accelerations in Ultimaker Cura?

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  • $\begingroup$ Looking at your last photo the cura print on the right. I see the waves on the top side of the cube to the right. This makes me think your infill/perimeter overlap is set too high. I use slic3r so 5% is my perfect number, but I don't know Cura well enough to find that setting. Lookup the infill/perimeter overlap equivalent setting in Cura and try to reduce that number and prevent the nozzle from overlapping too far to the walls. $\endgroup$
    – Athanasios Karagiannis
    Oct 18, 2017 at 21:23
  • $\begingroup$ I don't think that the waves are caused by infills because a) they are too small and b) they do not stretch across the complete vertical shell, but only at one side - always after the corner. $\endgroup$
    – Thomas S.
    Oct 19, 2017 at 5:37
  • $\begingroup$ It’s weird. I have an Ender 3 and get wavy walls except they go vertically. I think it has to do with Cura 4.1.0. When I switched to it, I was having problems with under extrusion, losing accuracy, etc. I’m going to go back to the old versions because it worked better. $\endgroup$
    – Jack Vandergriff
    Aug 1, 2019 at 1:16

3 Answers 3

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This defect that you see is called "Ringing" and is described in detail here.

In summary, these waves are seen when the print head makes a sudden change in direction in combination with high speeds and high accelerations. As the waves dampen in amplitude the further you get from the sharp corner, this is related to print settings rather than vibrations transmitted through the belts.

Apparently, the settings for Ultimaker Cura differ from the settings in Slic3r, there is no other explanation as the hardware is exactly the same. Reducing print speed and acceleration in Ultimaker Cura will reduce the ringing defects.

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Those wavy lines could be artefacts caused by closely-spaced infill, but they could also be resonance patterns caused by noisy stepper motors and over-tight belts. Since you have said that you have your belts nice and tight, I would suggest reducing the tension on them and see what happens. I know that some pundits say that it is not possible to have timing belts too tight, but I disagree with that. Belts should obviously be tight enough to eliminate free play in the system, and you may have a lot of latitude in the tensions that you can use, but if you make them drum-tight, they will transmit motor vibrations very effectively to the build plate (and onto your models).

If your stepper motors are noisy, you may want to invest in some vibration dampers. They can reduce noise and vibration significantly. Another solution would be to use more sophisticated stepper motor drivers, such as the TMC2100.

RepRapWiki: TMC2100

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  • $\begingroup$ Now the question is: if the belts would cause the problem, why this only is visible when using Cura and not when using Slic3r? $\endgroup$
    – Thomas S.
    Oct 19, 2017 at 5:38
  • $\begingroup$ This problem is due setting parameters, Slicer works smoothly with internal paramters, Cura works with more variables which we need to know. 3Dsymplify has also more parameters but allows to see results prior sending to print so you can adjust more efficiently. $\endgroup$
    – Fernando Baltazar
    Oct 20, 2017 at 16:25
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It is difficult to see with the lighting and the shiny green, but try printing a more complex object, like the usual XYZ cube. Does it look like this one? which means big waves after a change of direction, but then getting smaller?

enter image description here

If so, it is "ringing" or "ghosting", which means that the acceleration you set is too high for the mechanics of your printer and the machine vibrates too much.

Does it look like this one? Which means, exactly aligned vertically, and everywhere, not only after changes of direction?

enter image description here

Then it is NOT ringing, it is due

  • too tight belt (almost always!)
  • poor quality belt
  • poor bearings or idlers (not common)

I also had it and it was the belt, too tight. Loosen it, it can be much looser than you think before you get issues.

Check How to fix evenly spaced vertical print pattern to get more information about the second issue.

There is another potential cause for wavy walls, however I'm mentioning it for completeness, it is not the case of the question.

If the waves repeat horizontally, but are not aligned vertically, and the extruder is a direct drive, it could be caused by the issue explained in this video, which shows that the dual gear of direct drives introduce periodic changes in flow, which are visible sometimes.

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