I’ve volunteered to help a disabled author sign their name at book signings. We’ve settled on an AX4 (cheap China import) pen plotter with a GRBL controller. I’ve manually created a device in LB, and in the device settings tab, created all the entries for the machine on the “Custom GCode” tab (User start script, user end script, Tool on, Tool off, etc.)
When I use the “Save GCode” function on the “Laser” tab and send that saved file using the “Universal GCode Sender” (UGS) program, it works perfectly. The machine plots the design in the correct location without errors and then returns to the correct start position.
When I use the “Start” button (with “Start From: Current Position” selected) to send the design directly from LB, the plotter freaks out, banging the tool into the stops and ending in the completely wrong spot due to the errors from over running the tool.
There is no “Home” function or limit switches so UGS just starts the plotter plotting wherever it is. I’m thinking LB is trying to home the tool,or maybe move it to some initial start location that’s not part of the gcode. I’ve tried changing the “Start From:”, pressing the Home, Go to Origin, Set Origin, Clear Origin to no avail. The tool crashes either before or after the plot.
I’m at my wit’s end here. Any ideas? What am I missing?
In that case, you must simulate the Home function whenever you turn the machine on:
LightBurn assumes the machine is homed in the corner selected by the Device Origin dot:
You can pick any corner, but front left (lower left on the screen) will likely work best because then the coordinates march upward and to the right.
Then, before you turn the machine on, shove the pen carrier into the front left corner. When the power goes on, the controller will use that location as the (0,0) coordinate origin and so will LightBurn.
Set the LightBurn Working Size to match the physical / actual travel limits, minus a few millimeters in case the actual limits are slightly less than whatever the advertising claims.
Because homing without home switches never ends well:
Never hit the LightBurn Home button in the Laser Window
With the machine manually homed at startup, you can use LightBurn in Start from: Absolute Coordinates, lay out the signature as needed, and away it goes.