forgefirm/docs/LIGHTBURN.md

LightBurn setup & operation (ForgeFIRM, motion-only stage)

Status: motion-only. At this stage the laser cannot fire — the driver forces the hardware laser latch locked and never emits the laser bit in the pulse stream. A "job" runs every motion of the design (cuts at cut speed, travels at travel speed) with the beam off. Live fire is a later milestone, gated on the standing scope checks (BRINGUP.md).

One-time device setup

Prerequisite: the controller is running on the board (see BRINGUP.md; grblHAL_glowforge on TCP port 23 at 172.16.1.97).

1. Laser window → Devices → Create Manually (skip auto-find; it scans serial ports).
2. Device type: grblHAL if your LightBurn version lists it, otherwise GRBL — both speak the right protocol.
3. Connection: Ethernet/TCP. IP address: 172.16.1.97 (LightBurn uses TCP port 23 for GRBL devices, which is exactly where the controller listens).
4. Name: e.g. Glowforge ForgeFIRM. Work area: X 495 mm, Y 279 mm.
5. Origin: pick the corner where the head sits after parking at home — rear-left as you face the machine (the top-left dot in the selector). This is what keeps jobs un-mirrored: machine +X runs right, +Y runs from the rear rail toward you.
6. Auto-home on startup: NO. Homing is not wired yet; $H errors.
7. Finish. If a stale device profile already exists, edit its IP instead of creating a new one.
8. Device Settings (wrench icon): S-Value Max = 1000 (matches $30).
9. Optional backup: File → Export Devices → saves a .lbdev you can re-import later (the format is not editable text; export is the way to make one).

Job start mode (important on an unhomed machine)

In the Laser window set Start From: Current Position, and set the Job Origin dot to the same corner as the machine origin (top-left dot). The job then runs into the bed from wherever the head currently sits — absolute machine zero never matters, which is the forgiving mode while the machine has no homing switches.

(Absolute Coords also works, but only if the head was parked at the home corner when the controller started; after any Stop/alarm the absolute frame is stale until the controller is restarted with the head re-parked.)

Operating basics

• Frame traces the job's bounding box at travel speed — do it before every Start. There are no limit switches: framing is your crash protection.
• Start runs the job. Travels run up to 200 mm/s; anything faster in a layer is clamped by the controller ($110/$111 = 12000 mm/min).
• Pause = grbl feed hold: motion parks within ~0.4 s (0.2 s stream queue + deceleration); Resume continues exactly.
• Stop = soft reset: motion aborts with a controlled deceleration and grblHAL raises an alarm with position declared lost (the stream queue means up to ~40 mm of in-flight difference). Recovery: unlock ($X in Console or LightBurn's prompt), jog the head clear, and carry on in Current Position mode. Restart the controller with the head re-parked if you want a clean absolute frame.
• Move tab: jogging (set a sane speed, e.g. 6000 mm/min), Get Position, distance buttons.
• Console tab: raw grbl — ? status, $$ settings, $X unlock, $J=G91X10F1200 jog.

Air assist / fans

Each cut/engrave layer has an Air Assist toggle (in the layer's cut settings). Turning it on makes LightBurn emit M8/M9 around that layer, which drives the machine's full cut-profile ventilation: air assist to full, exhaust and intake fans to factory run speeds, then a ~15 s cooldown after the layer before returning to idle. Leave it ON for anything that will eventually involve the beam; expect real fan noise.

A good first job

1. Draw a rectangle (~100 × 60 mm) with a circle inside.
2. Double-click the layer color bar (bottom): mode Line, speed 50 mm/s (= 3000 mm/min; check Edit → Settings for your speed units), power anything (ignored — nothing fires).
3. Park the head where the job's rear-left corner should be (or leave it at home), Frame, watch the perimeter trace, then Start.

Expected behavior: darting travels at up to 200 mm/s, smooth 50 mm/s tracing of the shapes, silky and near-silent motion (factory currents + decay mode), and the head finishing per the job's return setting.