Wavy pattern

Hello everyone,

after changing my belts to GT2 20 teeth pulley my prints come out with wavy pattern on XY axes.
I have attached this mount [www.thingiverse.com] to one axis, and left another one with stock bearing mount.
My print speed is 30 mm/s, 0.2 mm layer height with 0.4mm nozzle.
These are photos of the pattern I am getting:

[onedrive.live.com]

Any help would be appreciated.

I had this problem up until a couple of weeks ago. Cutting to the chase...I found that with a little pressure I could make my hot end shift in it's mount.

So, as it printed it would shift to one position for awhile..and then it would shift to another, and then it would shift back. The key here was there would be layers printing in one position, shift to another and then return to the original position. If it shifts consistently in one direction, which isn't the case in your print, it would suggest skipped steps.

For backlash, it seems to be all over the board..printing a layer or 2 here and another layer a bit off and then another somewhere else.

I wound up adding (2) 8mm washers stacked on top of my hot end before tightening the retaining screws which locked it up nicely and my issue went away.

Make sure your extruder isn't wiggling...that may be 1 cause of the problem. I'm sure folks have seen others...

Edited 1 time(s). Last edit at 08/14/2014 10:19AM by ltklein.

Looks very much like an acceleration problem. When the direction of travel changes 90 degrees like that abruptly then everything tends to shake and oscillate a bit afterwards. If you turn down the acceleration values in your firmware it'll help smooth out those direction changes. Printing slower can also help. I'm still trying to completely eliminate this from my machine, but speed and acceleration are definitely the two main culprits.

What Opus said. That was my experience as well. And my remedy as well.