MDF is homogeneous, cheap and perfectly flat: ideal for jigs, models and anything that will be painted. In exchange, it is the material that dirties a machine the most and demands the best extraction.
Settings: what really matters
MDF is denser than plywood: at the same thickness expect roughly 20 % more power, or a lower speed. Its consistency is a huge advantage: a setting that works on one board works on the next, which is never guaranteed with solid wood.
The edge always comes out dark brown, almost black. That is inherent to the glue: do not try to avoid it by slowing down, you will only widen the burnt zone. Plan a finish instead.
When engraving, MDF gives strong contrast from 20 % power, but it digs in quickly: for a wide fill, several light passes beat one heavy pass.
Risks and precautions
This is the part not to skip: MDF releases a lot of resin-laden smoke and fine particles. Without effective extraction the workshop becomes unbreathable and lenses fog within tens of minutes, quietly sapping usable power.
Clean the lens and mirror more often than with other materials, and empty the tray: MDF debris is fine, dry and ignites easily.
Avoid moisture-resistant MDF (the green board): its treatment gives off extra fumes and the cut becomes irregular.
Finishing
MDF is made to be painted. Spray primer, a light 240-grit key, then colour: the result is cleaner than on any wood. Edges soak up finish — two coats of primer on the edges before painting avoid the blotting-paper effect.
If the piece stays raw, a dry cloth is enough: water swells MDF irreversibly.
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.