Engraving gives different depth for horizontals VS verticals

Hey guys !
I am using a 10 mW laser module to engrave PMMA with this file :

Note that there is no grey background on the file, its just the software background.

And I am getting this :

As you can see, horizontal parts are getting engraved more deeply.
Am I missing something ? A setting or something ?

Thanks a lot !

I’ve noticed similar as well when laser cutting materials. The cut will completely penetrate on one axis but not the other if I use a marginal setting. FYI, that’s using uniform materials, not wood, so I can’t blame the wood grain.

Interesting, and here I was blaming the wood grain!

So you got the same issue but never find out a solution right ?

Well my issue was just cutting, so I up the power to make sure it cuts through on both axis. I’ve never been able to successfully laser depths with any usable results. Just use it for cutting and surface etching.

I think that the issue will be related to the acceleration in the movements. On the picture, the movements are from top to bottom? (or bottom to top) and not left to right?

The short movement would mean that the toolhead is actually moving slower on the short segments, but the laser power is the same. So the same spot receives more energy on the short segments than on the longer segments. Hence the difference in depth.

If you don’t want this you need software that generates gcode that moves over the full path at the same speed and only fires the laser at the same needed spot.

Or as already suggested. Use cnc instead of laser if you want a reliable depth of cut.

Movements are from top to bottom. So its a lot of small back and forth moves for the part which is engraved too deeply.

Can you recommand me a software please ?
Thanks a lot.

Lightburn offers a lot more features than Luban and is nice to work with. (not free, but relatively inexpensive)

Not sure if it offers the feature you need and there might also be limitations in the firmware. @brent113 has a lot more experience with that.

But then again. If you want a reliable depth of cut. You really should use the cnc module and not the laser.