Changing M4 to M3 when outputting g code

I can connect and run a burn but the laser is moving too fast. The GBRL uses M3 and the lightburn uses M4. How do I switch the settings

Enabling “Constant Power Mode” in the cut settings is the easiest way to use M3. This won’t slow down the laser, though. But should match LaserGRBL in output type.

Where are the cut settings?

Cut settings are accessible by double-clicking the specific layer in the Cuts / Layers window.

One there, toggle the “Constant Power Mode” switch to enable.

Thank you. The laser is on but not burning the image

I thought you were asking about using M3 in order to get a specific look. Normally I’d advise against turning this on as there are real benefits to having variable power.

If you’re looking to dial-in your settings then you really only have 2 controls, speed or power. If the material is not burning then slow down or power up. Or a combination of the two. Keep adjusting until your desired look is achieved.

What is the best way to adjust the speed


Are you asking how to go about changing the speed at all or how to determine the proper speed?

If the former, then you need to get familiar with the Cut Settings Window. Well detailed in the documentation:
Cut Settings Basics - LightBurn Software Documentation

If the latter, you can determine this experimentally or by running a test pattern. Latest udpate from LightBurn now includes a Material Test tool that’s worth trying. Else there is a popular online generator here:

Lightburn PowerScale Generator - O2 Creative

Thank you. I think I got it working now. You have been a great help

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.