Laser problem - timing issue?

Hello, i am running a generic violet 2,5watt laser on my fan output (D9).
It is working great except for some timing issues. The laser stays on too long or fires to late on some lines.
I saw this kind of behaviour in a picture from a jtech tutorial (cant seem to find it right now…).

The gcode was created with the jtech-inkscape plugin.

Anyway, here is a picture attached… maybee someone will recognize this…

Also, i would like to see a wiring diagram to hookup the laser with TTL. The driver-board has an ttl-port which i currently are not using.
I have seen how the ttl should be hooked up, but cant see to find an example for wiring the 12v power to the laser.


disc_gcode.txt (1.33 MB)

Another photo…

I ran into that issue. I don’t remember what I did to fix it, but it is definitely speed/accel related. Some of the paid programs have more settings you can use to tune that out when you’re engraving in raster mode.

It was either: setting travel speed and laser speed to be the same (or at least close together)
slowing down both of the speeds quite a bit and turning the power down

You can definitely make it go away just by playing with the speed/power settings… or by using different software.

Hi Gyrnik, thanks for your reply.
When I use the inkscape-plugin, the laser moves very smoothly and without ever slowing down, but it creates these stripe artifacts.
When i use image2gcode (MPCNC edition) the CNC stops and jerks (around) every few steps, this creates some shaking-artifacts.

I did notice that it helps when I change the jerk and accelaration settings mid-print. But i still have too find the correct settings.

When i lookup youtube videos from mpcnc engravings, most of them just move smoothly without slowing down to burn something.

Would you happen to have a gcode file of which you know works fine on your mpcnc?

Kind regards,


How are you feeding your gcode? SD card or repetier host?

Repetier host

Try SD card if you have it.