Hi!
I need some assistance to solve this weird ripple I have on my X1C. It currently stands on a IKEA Bror shelf, the metal sheet version.
I have my suspicion that this is the culprit but I need it somewhat confirmed.
As you see in the image on the right model, printed in vase mode, it’s all fine and dandy. But when making a larger print with walls it gets really bad after about 14cm and above.
Your part is very tall and thin. So it’ll bend during printing the taller it gets.
You can stabilize it with supports, either hand drawn or using tree supports or by printing it flat.
Have a look through the Bambu Academy classes. I think the recently published A1 classes include something about stabilizing vertically printed lithos.
I recommend starting by checking the belt tension, and then running a calibration. The defect in the photo looks way too severe, even on lower layers.
It might also just be time for some basic printer maintenance — cleaning the rails with alcohol, replacing the grease, and so on. Most likely, it’s just time 
Check on YouTube the basic maintenance. This might help.
There is always some push with the nozzle as it ejects filament. The part will shift very slightly at first but as it gets taller the effect will be more pronounced. Cleaning rails and maintenance MAY help but you would be better off with some removable support bracing.
A calibration should be done and a check should be made to see if anything is touching the heated bed.
Thanks for the tips!
I’m going to try to tension the z-axis belt later this week and also do some calibrations. I’ve already tried relubricate the z-axis screws but there is no difference.
NOTE!
The tall print is just a test-model to visualize the issue 
