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Test fire Switch Macro for Light Burn

Instead of a physical three way switch or using the tiny test button on the laser power supply PCB, you can actually set up a macro in LightBurn that switches the controller to cnc mode which allows a timed test fire while the gantry is stationary.

Right click on the macro and enter a name and populate it with the $ settings and G-code commands as following (without the commentary):

$32=0 (to cnc mode)

S200 (strength 4 mA)

M3 (or M4 to switch on the LO connection)

G4 P1000 (or longer, dwell or pause command)

M5 (switch LO off)

$32=1 (restore to laser mode)

So when you click on the macro, it test fires for 1 sec which leaves a mark on the tape that you use to cover a mirror (don't touch it to the mirror surface but onto the rim). Start from 1st mirror at the tube and move toward the end (gantry). Adjust the mirrors and repeat across four corners of the laser. It's tedious and it can take a few hours to get a good alignment across all four corners.

Note: If you cannot align the dots on each mirror but got a misalignment of a millimeter don't worry too much, it will work well in practice. Anything more out of alignment indicates of a skewed gantry which can be solved by shims, washers or partly rebuilds...


Uploaded files:
  • Macro2.PNG
Cheers, Paul awesome.tech

Hi Paul.


I've attempted to create the macro in Lightburn 0.9.07, but noticed it doesn't finish. Does the macro work for you on the mentioned version? I've also opened a topic on the Lightburn topic, but we don't know what exactly is preventing the macro from finishing. There is a .gif file in the created topic, which shows the issue.


Thank you.

Thanks for this, yes maintaining software releases is an art, so the boys at LightBurn do their best to rectify the little bugs that creep in. Hopefully it is getting fixed soon. In the meantime you can use just the commands manually when aligning the laser beam.


Cheers, Paul awesome.tech

Paul, I used this Macro as you have written it here but when I select the button the K40 homes with no test fire. If I hit the button again it then does the test fire but after that the gantry is locked and I can't move it to another position. Sorry if there is a simple answer to this but I am a newbie as far as Grbl is concerned.

The gantry always "locks" to prevent it from loosing its position. You can disable this by replacing $1=100 or lower (255 sets it permanently fixed at the position).

You can always use the move menu to move the gantry around or enter the coordinates.

Cheers, Paul awesome.tech

Thanks Paul.

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