... I'm bilding/developing my own systems or refurbishing CNC-mills or rigid XY-plotters since maybe 35 Years - so no need the chinese clones
On the other hand, it seems, the Chinese previously copied/cloned my basic lasercutter design from 1995, where I've filed IP's for the type
For PCB-engraving: - I'm using fast-drying paints with high loads of carbon or pigment and clean it after engraving only with warm water, a bit soap and a soft brush.
Fibercoupled IR-laserdiodes with wavelengths of @808nm, @915nm or @975nm (have some with 5 and 9 Watts) works even better with black paint, but the blue 2W-laserdiodes have a smaller spot, so finer details possible.
I'm building and using my own drivers and firmwares+software too -- and had some time to optimize the applications ... so often I'm going a different way, what's not so easy to follow with the "cheapish" mentality
Viktor