Non-random layer banding on multiple printers

[drphil3d]

I've noticed this recently on two of my printers with identical hardware. Printing from Cura 4.1
klippy.log

[elliotf]

@drphil3d That looks like layer banding, which is usually a physical problem.

what do you have afor a Z axis? Is it a leadscrew? If so, what is the pitch of the leadscrew?

If it is a belted Z, perhaps your pulleys are out-of-round?

See also https://www.evernote.com/shard/s211/client/snv?noteGuid=701c36c4-ddd5-4669-a482-953d8924c71d&noteKey=1ef992988295487c98c268dcdd2d687e&sn=https%3A%2F%2Fwww.evernote.com%2Fshard%2Fs211%2Fsh%2F701c36c4-ddd5-4669-a482-953d8924c71d%2F1ef992988295487c98c268dcdd2d687e&title=Taxonomy%2Bof%2BZ%2Baxis%2Bartifacts%2Bin%2Bextrusion-based%2B3d%2Bprinting

[drphil3d]

Oh that's really interesting. I have a 4-start M8 threaded rod with a Z nut made from delrin. I also do have my heated bed running on waterfall instead of PID which could definitely contribute to the problem.

[drphil3d]

I was having some strange issue with git that wasn't allowing me to update to the latest version so removed the directory and reinstalled it, then enabled PID control of the heated bed which seems to have greatly improved things. Thanks