Laser always on full power

Hey folks, Thanks in advance for any tips here!

I have an OptLasers 6w laser, wired in and I’m using it for the first time.

  • Spindle PWM (and GND) of the X Controller are connected to the TTL & Signal Gnd of the laser
  • A separate 12V power supply is connected to the VCC & Gnd of the laser

I’ve created my design in Easel, and used G-Code Depth to Shades Converter to get my laser .nc file. My challenge is that no matter the laser power I use, the laser burns a hole in the wood I’m using.

I’ve tried by maple & oak to see if perhaps one wood was too soft. I’ve lowered the “speed” from the initial 179, to 50, to 10, to 2, and though S1 does seem to turn the laser off, S2 and all the others seem to produce the same laser strength.

Here’s the first few lines of my .nc file - any thoughts or suggestions? Thanks so much!

$32=1([ENABLE] GRBL Laser Mode)
G4 P0.01( ;Dwell, wait for sync)
G4 P4.0(; Dwell 4.0 seconds)

M4 S1
M4 S1(; Laser OFF)
G0 X21.086 Y28.295
M4 S2(; Laser On @ Power Level: 179)
G1 X21.166 Y28.452 F762.0
G1 X21.072 Y28.384 F762.0
G1 X21.132 Y28.148 F762.0

Check your $30 setting. Most likely it’s 1 (set it to 255 for testing).

Are you running a laser enabled grbl?

I think you want to be using M3 instead of M4 to fire the laser. M4 is the constant power per rate setting so the power varies based on speed from what I understand. and M5 to turn off the laser.

Yes, I didn’t notice that. There are some Laser programs that automatically use M4 and you as the user cannot change it.

The one that comes to mind is LightBurn.

Thanks for the suggestions! Indeed, LarryM hit the nail on the head: my $30 was set to 1, rather than the 255 my gcode expected.

I still have other problems getting a good text engraving, but I’ll do some trial and error and attempt to battle those for a while before I come back with some intelligent questions!

Appreciate the help!

1 Like

Travelling the laser highway myself, it can seem a bit daunting until you get your head wrapped around the concepts and procedures involved.

If you dont understand what the problem is, then pretty much anything you ask is an intelligent question on some level. The foolish questions are those that are asked, then reworded and asked again repeatedly. And when the answer is given the person with the query fails to heed the advice or takes offense to the advice given.

Those little beams of light have the potential to be destructive ( burning the friggin garage down) or downright dangerous (protect your eyes)
Dont be afraid to ask.