Ah – still learning – this gcode was created from a ‘laserengraver’ plugin for Inkscape – deleting the line with the outsized I/J values:
G02 X82.0769 Y29.6052 I21644.8026 J-86331.8286 <– unusually large I/J
which barely draw anything in simulator – and it works fine. Tuned my setup with running the json serial port server on an old box in the garage and sending from Chilipepper on a more powerful notebook and worked perfectly several times (testing feed rates on different types of wood)
Problem solved, happy lasing.
Also, drawing tiny letters at 300mm / minute really makes the motors sing 😉 I’m impressed with this controller.