Acrylic is one of the best materials for laser cutting — it cuts cleanly, produces polished edges in a single pass, and is available in a huge range of colours, patterns and thicknesses. Whether you are cutting signage, jewellery, model parts or architectural elements, understanding how acrylic behaves under a laser helps you get the best results.
Cast vs extruded
Cast acrylic and extruded acrylic behave very differently under a laser. Cast acrylic produces flame-polished, crystal-clear edges — the laser vaporises the material cleanly, leaving a smooth, glossy cut face. This is the standard choice for high-quality laser work. Extruded acrylic melts rather than vaporises, producing frosted, slightly rough edges that need post-processing to achieve clarity. For engraving, the difference reverses: extruded acrylic produces a cleaner, more consistent white frost when engraved, while cast can produce a more variable, slightly translucent mark.
For cutting, always specify cast. For engraving (especially filled or painted engraving), extruded can be the better choice.
Settings
Laser settings depend on your machine's power, the material thickness, and whether it is cast or extruded. As a starting point for a 40-60W CO2 laser cutting cast acrylic: 3mm sheet at around 15-20mm/s and 80-90% power; 5mm sheet at around 8-12mm/s and 90-100% power; 10mm sheet typically requires two passes or a higher-powered machine. These are guidelines — always run test cuts on scrap material and adjust. The goal is a single clean pass that cuts through completely without excessive charring or melting on the back face.
For engraving, reduce power significantly (20-40%) and increase speed (200-400mm/s). Multiple light passes at lower power produce a cleaner engraving than a single heavy pass.
Safety
Laser-cutting acrylic produces acetic acid vapour (a vinegar-like smell) that is mildly irritating but not highly toxic in ventilated conditions. Good extraction and ventilation are essential. Never laser-cut PVC or vinyl — these produce hydrochloric acid gas that is both toxic to breathe and corrosive to the laser's optics and mechanics. If you are unsure whether a plastic is acrylic or PVC, check with the supplier before cutting. Polycarbonate should also be avoided — it melts, discolours and produces poor results.
Tips for clean cuts
Leave the protective masking film on during cutting — it prevents smoke residue from staining the surface around the cut line. Peel it off after cutting for a clean finish. Ensure the sheet is flat against the cutting bed — warped material produces inconsistent focus and uneven cuts. Use a honeycomb bed or knife-edge supports rather than a solid bed, as a solid surface reflects the laser back into the underside of the material and causes rough edges. Clean the lens and mirrors before cutting — dirty optics reduce power and produce inconsistent results.
Troubleshooting
Incomplete cuts: Power too low, speed too fast, or the material is not flat against the bed. Reduce speed or increase power in small increments.
Excessive melting or charring: Power too high or speed too slow. The laser is putting too much energy into the material. Increase speed or reduce power.
Flame-ups: Most common with thicker material or when cutting enclosed shapes (the centre piece traps heat). Pause and let the material cool. Ensure extraction is pulling fumes away from the cutting zone.
Frosted edges (on cast acrylic): Usually caused by extruded acrylic being sold as cast. Check with your supplier. Also occurs if the laser is slightly out of focus — recalibrate the focal distance.
