I've successfully engraved an image with LaserWeb3 and grbl 1.1e.

I’ve successfully engraved an image with LaserWeb3 and grbl 1.1e. Tonight I’ve installed grbl 1.1f on the engraver and LaserWeb4 on the Raspbery Pi.
It looks like my previous grbl settings were preserved.

However, when I try to engrave a test image (as per instructions at cncpro) the laser doesn’t even burn through paper.

What am I doing wrong?

I’m having power issues with my Power Supply/Tube so it was hard for me to know what was causing my issues, but with help from Peter and others I got it nailed down. Do you have a mA Meter on your machine? If so, what’s it showing while engraving is going on.

Here are the things to look at:

  1. Settings. As Peter said, likely in your S value. I’m not sure about GRBL, but I my config wrong in Smoothieware. My PWM frequency was too low and Max Power was low as well.

  2. G-Code. If you feel like you have settings correct then use the “EYE:” button on the G-Code section (Blue Btn in Attach). Looks at the S Values being generated. YOu should see codes G1 X (Coord) Y(Coord) S (#) where # an value 0 to 1

Here is a small portion of G-Code from a raster engraving…

G1 X0.3 S0.59
G1 X0.45 S0.62
G1 X0.6 S0.59
G1 X0.75 S0.61
G1 X0.9 S0.60
G1 X1.05 S0.60
G1 X1.2 S0.60

  1. If you still have the Potentiometer in your circuit, then what ever S values will be a percentage of that. So if it is set at 10ma, the an S0.5 is going to be 5ma. If its really low, then that can be the issue.

  2. If you have and LCD panel on your Grbl Controller than use the Test Fire features to test different power levels.


I did not know that. I thought it was same as Spindle speed which I believe on my CNC is 0-1 as Smoothie is. Learn something new everyday! Some days its 2 things.

figured it out: combination of laser not quite in focus and cut rate too high.
I must say the new LaserWeb 4 is great. It’s much easier to create a nice raster of a bitmap.