OMTech 40W CO2 Settings for Acrylic (PMMA)

Cutting Settings

How to Set Up Acrylic (PMMA) on the OMTech 40W CO2

1. 1Secure your acrylic (pmma) flat on the work bed using clamps, magnets, or a honeycomb pin set to prevent movement during the job.
2. 2Set your focus distance accurately — use the auto-focus probe if your machine has one, or measure manually with the focus gauge.
3. 3Ensure your water cooling system is running and the coolant temperature is between 15–25°C before starting the laser.
4. 4Enable air assist if available. A steady stream of air at the cut point removes debris, reduces charring, and helps prevent flare-ups.
5. 5Enter the speed, power, and pass count from the settings table above into LightBurn. The table lists both mm/min and mm/s — LightBurn defaults to mm/s, so use the mm/s value unless you have switched units. Use the “Cut” or “Engrave” layer settings panel.
6. 6Run a small test cut or engrave on a scrap piece of acrylic (pmma) before committing to your final project piece. Adjust power up or down by 5–10% based on results.

What to Expect When Lasering Acrylic (PMMA)

CO2 lasers produce beautiful flame-polished edges on acrylic — the cut edges will be smooth, clear, and glass-like without any additional finishing. Engraving creates a frosted white appearance that contrasts well against colored acrylic. Expect some acrylic vapor during cutting; ventilation is important. The 40W CO2 tube produces clean cuts on most non-metals, often in a single pass. Its 10.6µm wavelength gives acrylic a flame-polished edge that diode lasers cannot match, and cuts run faster and cooler than any diode at a comparable task.

Common Mistakes to Avoid

• ✗Running at full power on the first attempt — always start with a test piece at the recommended settings and adjust incrementally. Going straight to maximum power risks burning through the material or causing fire.
• ✗Treating a CO2 laser like a diode and running slow multi-pass cuts — at 40W you can usually cut in a single faster pass, and over-slow cuts melt edges and waste tube hours.
• ✗Not removing the protective paper masking after cutting — leaving it on too long can cause residue that is difficult to remove. Peel it off soon after cutting.
• ✗Cutting acrylic that is cast vs. extruded without adjusting settings — extruded acrylic melts differently and may produce uneven edges.

Tips for Acrylic (PMMA) on Laser Machines

• ✓CO2 lasers produce flame-polished edges on acrylic automatically.
• ✓Diode lasers cannot cut clear acrylic -- use dark or opaque colors only.
• ✓Leave the protective paper on while cutting to prevent surface marks.
• ✓Reduce speed for thicker sheets to ensure a full clean cut.
• ✓For engraving, use high speed and moderate power to get a frosted white finish.

Frequently Asked Questions

Other Materials for OMTech 40W CO2

Acrylic (PMMA) Settings for Other Machines