Best Laser Settings for Cutting Acrylic (Clean, Flame-Polished Edges)
The best laser settings for cutting acrylic use high power at a slow, steady speed in a single pass, with air assist turned down low. On a typical 40 to 60 watt CO2 laser, 3 mm cast acrylic cuts well around full power at roughly 10 to 15 mm/s. Cast acrylic cuts with a naturally clear, flame-polished edge; extruded acrylic cuts faster but leaves a duller edge, so cast is preferred for display pieces.
Cast vs extruded acrylic (this decides your edge)
Cast acrylic is made in sheets and laser-cuts with a beautifully clear, flame-polished edge, it is the choice for signs, awards, and edge-lit pieces. Extruded acrylic is made in a continuous process, cuts a little faster and cheaper, but leaves a frostier, duller edge and can be more prone to melting. If the edge will be seen, use cast. If you are cutting hidden structural parts, extruded is fine.
A safe starting point for settings
Settings depend on your exact machine, but as a starting point for 3 mm cast acrylic on a 40 to 60 W CO2 laser: full power, 10 to 15 mm/s, single pass. Thicker material means slower speed or a second pass. Always run a small test cut and adjust: if the piece does not fully separate, slow down or add power; if the edge is bubbling or catching, you have too much power for the speed.
Air assist: low, not high
Counterintuitively, acrylic likes gentle air assist. A strong blast cools the cut and disturbs the melt, which frosts the edge and can even cause flaming to worsen. A low, steady stream clears smoke without ruining the flame-polish. This is the opposite of wood, where you want strong air assist, so if you switch materials, change it.
One clean pass beats several fast ones
For a clear edge, one slow pass that melts through cleanly beats three fast passes that leave ridges and re-melt lines. Multi-pass cutting is for thick material your laser cannot get through in one go. When you can, dial in a single-pass cut.
Diode lasers and acrylic (the catch)
Most blue diode lasers cannot cut clear or transparent acrylic at all, the blue light passes straight through. Diode lasers can cut dark, opaque, or specially formulated laserable acrylic, but not clear. If you have a diode laser and want to cut clear acrylic, that is a job for a CO2 laser. Check your acrylic is diode-compatible before you buy a sheet.
Safety first
Only cut genuine acrylic (PMMA). Never cut polycarbonate (it is often sold as acrylic but scorches, yellows, and will not cut cleanly) and never cut anything containing PVC or vinyl, which releases toxic, corrosive chlorine gas. Run your exhaust, and do not leave a running laser unattended, acrylic can flame.
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Make a cut-ready SVG for acrylicFrequently asked questions
What settings cut 3mm acrylic?
As a starting point on a 40 to 60 W CO2 laser: full power, 10 to 15 mm/s, single pass, low air assist. Run a test cut and adjust, exact numbers vary by machine.
Is cast or extruded acrylic better for laser cutting?
Cast acrylic gives a clear, flame-polished edge and is best for anything visible. Extruded cuts a bit faster and cheaper but leaves a duller edge and melts more easily.
Can a diode laser cut clear acrylic?
No. Blue diode light passes through clear acrylic. Diode lasers can cut dark or opaque laserable acrylic, but clear acrylic needs a CO2 laser.
Why is my acrylic edge frosted instead of clear?
Usually too much air assist (which cools and disturbs the melt) or you are using extruded acrylic. Turn air assist down low and switch to cast acrylic for a glassy edge.
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