Although my machine is not really fast enough for raster engraving I just had to give it a try.
This image of Jacko is engraved into glass, it is only monochrome so there is no PWM control of the laser at this stage – it is either on or off and controlled by the M11 and M10 commands.
However, when making the laser control circuit I incorporated a spare TTL gate in the trigger path which will allow me to logical AND two control signals – one being the existing on/off trigger (M11 & M10) and the other being a PWM signal derived from the spindle setup (S0 to S100). The PWM will vary the duty cycle of the applied laser pulses from approx 1% to 99% and provided I get the pulse repetition frequency correct should allow for true raster engraving with variable depth. Mach is not quite ready for this type of operation yet but I am sure that if enough people want it the necessary modifications will be made and Mach will become a full blown laser control software.
Tweakie.