OMTech 40W CO2 Settings for Glass

Engraving Settings

How to Set Up Glass on the OMTech 40W CO2

1. 1Secure your glass 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 glass before committing to your final project piece. Adjust power up or down by 5–10% based on results.

What to Expect When Lasering Glass

Lasering glass creates a frosted, white-etched appearance on the surface. The laser micro-fractures the glass surface rather than vaporizing it, so you are limited to engraving only — cutting glass with a laser is not possible. Results look best on flat, untreated glass. Apply a thin layer of wet newspaper or dish soap to the surface before engraving to improve finish quality and reduce chipping. 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.
• ✗Attempting to cut glass with the laser — lasers can only engrave glass, not cut it. Trying to cut will crack or shatter the piece.
• ✗Using tempered glass — tempered glass can shatter unpredictably under the thermal stress of laser engraving. Only use regular annealed glass.

Tips for Glass on Laser Machines

• ✓Apply a thin layer of wet newspaper or paper towel to the glass surface before engraving to dissipate heat and reduce chipping.
• ✓Use lower resolution (250-300 DPI) to avoid overlapping passes that overheat the glass.
• ✓A light mist of water on the surface helps produce a cleaner frosted finish.
• ✓Engrave at an angle if possible -- some users tilt the glass 1-2 degrees to reduce back-reflection.
• ✓Flat glass gives the most consistent results. Curved surfaces (mugs, bottles) require a rotary attachment.

Frequently Asked Questions

Other Materials for OMTech 40W CO2

Glass Settings for Other Machines