The paint is infused into the glaze. Have to dog out mu USB microscope to take closeups and post them here.

I wanted to thank tweakie for the help he gave me setting up my laser module. My controller is a chinese mach3 usb MK4-V. Gating pwm and output 1 (dir+/-) was not easy for me as I had no idea. The setup in the attachment worked for me. All the credit to Tweakie.cnc

Thank you for the praise 

Excellent solution, I am pleased that you have your laser working.

Tweakie.

The glass CO2 laser tubes have a finite lifetime after which they need to be replaced. Over the years this thread has been running I have fitted 4 or 5 replacement tubes and the latest one has just started to loose power output. Whilst waiting for a new tube to be delivered I decided to try a 5.5 watt diode laser to see if it would laser engrave this little aluminium panel. Although it operates at the blue end of the spectrum I was surprised to discover just how well it performed. Producing this panel was a two stage job using Mach4 to profile cut the aluminium blank (with a rotary cutter) and a laser to do the actual engraving. With a ‘stepover’ of 0.08mm the vector generated toolpath for the engraving had a process time of just over 4 hours which is really not so good. In comparison the raster engraving process time was just 27 minutes. This time saving relates to the number of times an axis has to change direction and of course stop. Although each deceleration / stop / acceleration time may be minute they all accumulate and with a vector toolpath there are many, many thousands of direction changes. Certainly for me, when it comes to lasers, raster engraving is the way forward.
Unfortunately Mach4 does not yet support raster engraving, perhaps one day it will but in the meantime, sadly, alternative machine control software had to be used.

Tweakie.