Laser will fire during framing but not during project run

[jamesalter (james trussell)]

I have Two Trees 3018 pro with the 5.5W circular laser module.
The laser will fire during framing and from the fire buttion. When using the fire button I can change power level from 0 - 20% (that is the max power on the fire button), with a obvious change in power output. (the wood burns.). The laser will not fire during project run.

Here are my machine settings.

Here are device settings.

Here is the gcode for my test project.
; LightBurn 1.4.05
; GRBL device profile, absolute coords
; Bounds: X7.01 Y4 to X90.07 Y62.05
G00 G17 G40 G21 G54
G90
M4
; Cut @ 700.002 mm/min, 50% power
M9
G0 X7.005Y4.003
; Layer final
G1 Y62.047S500F700
G1 X90.068
G1 Y4.003
G1 X7.005
M9
G1 S0
M5
G90
; return to user-defined finish pos
G0 X0 Y0
M2

Any help would be appreciated.

James.

[JTR (Tyler Raps)]

What are the X and Y maximum rates for your machine? You can see those under “Outputs setup” in the Machine Settings window.

If you exceed those maximum rates, power will be downscaled when you’re using Variable Power mode. For a 3018, they may be quite low (around 500 mm/minute), so the 700 mm/minute you’re setting could exceed that.

You can try slowing down, or turning on Constant Power mode in the Cut Settings Editor.

GRBL: Low or No Power Output - LightBurn Documentation

[jamesalter (james trussell)]

The laser functions with Constant Power. Variable power does not work at any X - Y maximum rate between 100 - 500 mm/min.

While I have your attention, is there a error log in Lightburn to see what errors I’m getting druing a run? When I generate gcode and run it on LaserGRBL, I keep getting a M4 command not supported error. I am running GRBL 1.1h on my machine.

[JTR (Tyler Raps)]

Try entering $32=1 in the Console window to enable Laser mode (and Variable Power mode).