printing artefacts similar to Z-axis wobble

#1 · 2023-02-28, 14:36

Hi,

I purchased a second-hand CB3 3D printer, but I'm having trouble identifying the cause of a particular issue. The problem is that certain layers are protruding in a uniform manner, leading me to believe that the Z-axis is wobbling. However, upon closer inspection, it's clear that this isn't the case. The protrusion occurs in all directions within the layer, and it only happens when I print parts that require support or other components are printed too. In contrast, when printing a cylindrical part separately, there are no defects.

I've tried using four different slicers (Craftware Pro, Prusa, Cura, Simplify 3D) and experimented with nozzle sizes ranging from 0.25mm to 0.8mm, but these artifacts continue to appear, and only their size changes with nozzle size. I've checked the belt tension and screws and found everything to be in order. Additionally, I've ensured that the latest firmware is installed.

Despite my efforts, I'm still struggling to pinpoint the source of the issue. Could you please provide me with some suggestions on what to check or what settings may be causing the problem? I'm becoming increasingly desperate for a solution.

Many thanks,
Zsolt

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#2 · 2023-02-28, 15:48

Dear Zsolt,

Can we take a look at the G-Code as well?

One possible reason could be that you use adaptive layer thickness with a wide range and permissive modulation, so the slicer switches from a low layer thickness to a high one. To rule it out you can examine your G-code in the CraftWare Pro Layer thickness GCode view
If it is related to the tensioning and the pulleys, then the direction of the movements could be a factor so the Gcode helps there too. (We can take a look at it)
If it is Z wobbling then the periodic occurrence should be independent of the used layer thickness. Try to print an object with a constant 0,1 mm layer thickness and the same object with a constant 0,3 mm. Measure the length of a period. If the periodic lengths are the same, it is wobbling.
It could be still related to the Z axis and not being a wobbling issue. Please disable all ZHops, and print the same object without Zhops. If it helps, the problem is the Z-axis bearing.

I hope these steps will help you identify and solve the problem.

Best Regards,

András

#3 · 2023-02-28, 16:22

Hi András,

Thank you for your answer.

Regarding the adaptive layer thickness, it wasn't turned on and, as I have mentioned, I tried different slicers too. Also, with the very same settings, if I print a simple object, like a cylinder there are no artefacts.

I also used different layer heights, z-hop on/off, tried with basic factory settings using the easy slicing method, tried set the extrusion speed the same for everything, disabled/enabled retract, low/high speed, etc nothing did matter just whether I print a complex geometry and/or multiple parts and/or using support.

I'll slice an object with 2-3 different slicers with the same settings, share the g-codes and will take pictures about the results on the weekend.

Zsolt

#4 · 2023-03-17, 09:39

Hi,

I've tried a few times in the past week to upload the gcodes and the images, usually just got a blank page, nothing was uploaded or happened.

Anyway, I try again. Now I try the images first then the gcodes separately.

I used 2 slicers, CW Pro and Prusa. In CW Pro I used the smart, the easy and a custom settings. I tried to make the layer heights the same and apart from the smart, I think I managed to do it, also tried to use similar infill and wall thickness. Overall, all prints came out within similar times.

Thanks,

Zsolt

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