Epoxy resin, alone or reinforced with fibreglass (laminate, FR4 circuit board), must not be laser-cut. The resin burns, the glass fibre does not cut, and the fumes are genuinely bad.
What actually happens
Glass fibre needs enormous energy to be cut: long before you get there, the surrounding resin has burnt over several millimetres. The line is brown and powdery, and the laminate delaminates.
Epoxy degradation releases compounds that irritate and sensitise the airways. Some laminates also contain brominated flame retardants whose combustion products must be avoided entirely.
Glass dust is abrasive: it works into the linear guides and prematurely wears the machine's mechanics.
Cast pieces and the alternatives
Cast resin pieces (jewellery, trays, river tables) raise the same problem: the resin burns and yellows, with no clean cut. Surface marking gives a dirty result and a stubborn smell.
To cut a laminate or a circuit board, a CNC router with extraction is the answer — it is the industry standard anyway.
For a clear cast part, cast acrylic cuts and engraves perfectly with a CO2, with a far better result.
Every figure on LaserSettings comes with the machine, the laser source, the material and the thickness it was tested on. A setting published for a 10 W diode says nothing about a 40 W CO2, and a setting for 3 mm says nothing about 6 mm: check those four things before you copy any number.
Settings are confirmed or disputed by the members who reproduce them, so reliability comes from cross-checking rather than popularity. Photos of the result — cut edges, engraving shades, scorching — tell you more than a single number found on a forum.
Whatever the material, treat a published setting as a starting point: run a small power/speed test grid on an offcut, clean the lens, redo the focus, work with fume extraction and air assist, wear glasses rated for your wavelength and never leave the machine unattended.