Learn/Plasma/Toolpath Generation & Post-Processing
G-Code Post-Processor
Updated v2.3.2At a glance
- Outputs LinuxCNC / Mach3 compatible NGC format
- G90 absolute positioning, G20/G21 unit selection
- M3 torch on, M5 torch off, G4 pierce delay
- G0 rapid moves, G1 feed moves
- Native G2/G3 arc moves — arcs are not unnecessarily linearized
- Z-axis retract between each cut contour
- Bundled QtPlasmaC / LinuxCNC post supports center-spot pierce and skip semantics via [spot] markers
- FLCNC / FangLing and ProMach plasma posts bundled alongside GRBL, FluidNC, and QtPlasmaC
- Fusion 360 post-processor also available for workflow flexibility
The post processor turns generated toolpaths into G-code for your controller. Posts are .jcpst
files — JavaScript run in a sandbox with Fusion 360-style Format and Modal helpers — and each
machine profile selects one on its Post tab, filtered to plasma
posts only. The upstream pipeline hands the post exact arc geometry, so the post decides whether to
emit native G2/G3 I/J arcs (most do) or linearize for controllers that can't take them.
Bundled plasma posts
LinuxCNC Plasma, QtPlasmaC for LinuxCNC (material blocks, small-hole spotting via [spot]
markers and M3 $2, THC envelope with M62/M63, hole velocity reduction through M67 E3 Q),
Mach3 and Mach4, GRBL for GRBL/grblHAL/FluidNC controllers, FluidNC Plasma for GcodePilot-run
machines (torch fire via o<fire_torch> subroutines and AVTHC M101/M102/M103 — see
Arc Voltage THC), FLCNC / FangLing F-series shape cutters,
PromachLTD StrikeCommand, FastCut CNC G7, and JetFlight.
What the output looks like
G20/G21 units and G90 absolute positioning up front, then per contour: a G0 rapid to the
pierce point, Z to pierce height, M3 torch on, G4 pierce delay, feed down to cut height, the
cut as modal G1/G2/G3 moves with the recipe feed, M5 torch off, and a retract to safe
height between contours. Comments identify the program, machine, recipe, each part, and each
contour by id and type, so the file reads cleanly at the controller.
Customizing
Every post exposes properties on the machine's Post tab — file extension, linearize arcs and arc
deviation, coordinate decimals, safe Z height, path blending — saved per machine. The pencil icon
opens the post source in the built-in editor for full control, and Import & Convert takes an
existing SheetCAM .scpost or Fusion 360 .cps post and converts it to a JetCad3 post through the
jetcad.io AI service (sign-in required).