Problems! Waves when engraving small and short parts

Hi! :grinning: I have an atomstack A5 and when i try to engrave small letters or vectors it does a sort of wave at the beginning of the segment! (when engraving long lines long x or y it’s everything fine).
I’ve tried so many things, from switching motors y to x and viceversa, I’ve loose the belts, I’ve tightened the belts, I’ve changed all 9 wheels, I’ve checked with a mate every sort of tool I could check. The problem is already there.
I think it’s a motor or software problem, because I’ve tried to engrave moving by hand the laser module but it does not do these waves. (see picture) :innocent:

This is the vibration of the laser head. It’s a mechanical problem. You need to make sure that the head runs smoothly and tightly along the frame. Touch the tip of the head slightly with a finger - does it move/wiggle?

If you can’t rule out the mechanical cause, you can decrease the acceleration (firmware parameters $120 and $121) to reduce the wobble. But this won’t cure the original problem.

In my opinion this is 100% mechanical. too much gap in the wheel bearings, loose carrage screws, possibly a bit of slippage in the drive shaft collars or belts. It appears to be happening when there is a change of direction on the Y axis and that would lead me to think the whole bridge was wobbling. I would start checking for play in the Y axis drive components.
Try this, with the laser off and sitting midway of the x and Y axis, grab hold of the coupler on the right hand side of the drive shaft for the y axis and check for any play. Next try and rock the bridge assemby back and forth, not pushing it, rock it. do this on both sides. After that I would check for play in the laser head,but I would assume you’ve checked it for play. Good luck.

Update! I tried to tighten the elliptical wheel on the X and it started to go better, not all problem solved but in the way. Here’s a photo! i also reduced the acceleration on oth axis and that’s the result. i’m only asking myself if tightening wheels so much won’t create other problems!