Issues with a sort of ringing and jagged cuts with print

[TechnoTan]

Hello!

We've had our K1 Max for a while now with minimal issues. Suddenly, our newest print is having this consistent issue of ridges and almost imbalanced looking printing as it gets towards the end of the print. It is primarily a vertical print, and the higher it goes, the more frequent these rings get.

Our first thought is that maybe it is getting wobbly towards the top? But we have slowed down the printing speed so much and it is still occuring.

A local expert has said it shouldn't be the file, however, we are test printing another different file now.

Here are some photos:
https://imgur.com/a/RHNMRPp

Any help and expertise would be very much appreciated!

[Bikeracer2020]

I've seen clips on Youtube about the vertical ringing lines on prints and there seems to be some evidence that it's caused by harmonics from the belt, pulleys and stepper motors on a coreXY machine.

Bambu labs have suggested to use higher speeds to alleviate this, and speeds of around 130/sec will show this and slower will make it more pronounced.

I have noticed this myself on my X1C, I was getting a visible line pattern at around 130/sec and it was more pronounced at 120/sec.

[TechnoTan]

Hello! Thanks for the pointers- we will give it a go with faster speeds.

[TechnoTan]

Turns out it was the print wobbling as it got through to the top part. Adding supports fixed the issue! Thanks for the help.