Oddly spaced horizontal interval lines

[Mathew Hamas]

Hello, I am at a complete loss with one of my lasers. It's a monport 55w, brand new.
After running tests today I have discovered my issue only happens when engraving bi directionally. It is horribly consistent and happens in every corner of the cutting bed.
I have adjusted belts, inspected pulleys, lowered acceleration speeds, engraving speed/power, and much more. Nothing seems to get rid of it. I am all ears if anyone has a possible solution. I'm thinking there is a controller, stepper, or software issue but I'm not sure.

The attached picture.. lines on the left is with bi directional on and the lines on the right bi directional is off
Thank you

[Edouard Connor]

Maybe these will help you: https://docs.lightburnsoftware.com/Scan ... tment.html

[Gene Uselman]

I would suspect a mechanical problem- a bit of looseness somewhere. When checking the pulleys, there are sometimes two grub screws- one tightens to the shaft and the second one locks the first.