Grbl, for the last year or more (since version1.1f), has used the same M3/M4/M5 gcodes to control both a spindle or a laser. And we were having to use the M106/M107 fan control gcodes to control the laser… Marlin’s M3/M4/M5 gcode only seemed suited for spindle control IIRC. Marlin definitely showed the effects (darkened, overburnt edges) of starting/stopping at each block boundary and no laser power adjustment as the carriage accelerated and decelerated to speed.

Using the “tones”/shaded blocks, I tried to make the side-by-side pictures similar enough to get a general idea of the overall “balance”/contrast of light and dark blocks for each run.īut what we were actually testing at the time was the “overburn”/acceleration effects on the shaded blocks as the laser power changed from block to block… especially apparent on the 50 mm/s (3000 mm/min) run. The Marlin tests were conducted over a year ago… in a different city, a different house, under different lighting conditions, with a different camera, different CNC machine, different controller, different firmware, and different gcode generator/post-processor.

TBH I’m shocked the comparison is as similar as it is… given that the only thing these two tests had in common was the test image, material, feedrates, and resolution.

Lightburn camera distance