Running a laser under Mach3 uses the spindle control path rather than a dedicated laser controller. The configuration lives in two places: the Spindle Setup tab under Config → Ports and Pins, and the Mill Options section for axis behavior.
Spindle Setup Laser Mode
Open Config → Ports and Pins and select the Spindle Setup tab. In the box labeled Special Settings, enable the laser mode option that ties laser frequency to feedrate percentage. This couples the laser's modulation frequency to the commanded feedrate, so energy delivered per unit of travel stays more consistent as the feedrate changes — the core requirement for cutting and engraving with uniform power density.
Inhibiting the Z Axis
Laser work is planar; the Z axis should not respond to toolpath moves. Under Mill Options, enable the option to inhibit the Z axis. With Z inhibited, the head holds a fixed standoff from the workpiece while X/Y execute the cut profile, preventing unwanted plunges from toolpath Z commands.
Verification
After configuring both settings, confirm on the Settings page that the mode is active before running a job. Then dry-run a known toolpath and check that (a) the spindle/laser output tracks feedrate percentage changes and (b) the Z position remains fixed throughout the program. Only enable the laser once both behaviors are confirmed on an unloaded run.
FAQ
Where is laser mode in Mach3?
Under Config → Ports and Pins, on the Spindle Setup tab, in the Special Settings box — it provides a laser mode with frequency tied to feedrate percentage.
How do I stop the Z axis from moving during laser cutting in Mach3?
Enable the Z-axis inhibit option under Mill Options. The Z axis then holds position while X/Y follow the toolpath.
Why tie laser frequency to feedrate percentage in Mach3?
Coupling laser modulation frequency to feedrate keeps delivered energy per unit of travel more consistent as feedrate changes, producing more uniform cut depth and engraving density.
