What is CO2 laser cutting and how does it work?

When it comes to cutting items out of a sheet, a laser cutter is frequently the best option due to its precision and speed. However, not all laser cutters and engravers are made the same or have the same capabilities.  

CO₂ laser cutters are among the most popular laser cutting machines. Hobbyists can purchase or create small CO₂ laser cutters that can engrave wood and leather, cut paper, and work with specific plastics. Product designers that want to cut metal sheets, as well as particularly thick wood and plastic, will need a more powerful industrial laser cutter. This article explains what a CO₂ laser cutter is and how they work. Read on to find out what distinguishes these CNC laser cutters.

What Is CO₂ Laser Cutting？

Simply put, a CNC laser cutting machine uses high-intensity light to vaporize material from a workpiece with ultra-fine precision. Controlled by a computer, the laser head cuts shapes from material sheets. It can also create slots and bore holes with high precision to meet design requirements. A CO₂ laser cutter – also called a carbon dioxide laser – differs from other CNC laser cutters in how its laser is generated and directed to the workpiece. It uses electricity and a gas mixture (including carbon dioxide) to produce high-intensity infrared light, which is then directed and focused into a continuous beam via a series of mirrors and lenses.

How Does a CO₂ Laser Cutter Work?

CO₂ laser beams are generated in an airtight glass discharge tube—filled with a gas mixture (including nitrogen, helium, and light-emitting carbon dioxide) and fitted with mirrors at both ends. A high electrical voltage is applied through the sealed tube to excite gas molecules, producing light.

The infrared light from CO₂ lasers has a wavelength that travels easily through the air, preserving intensity. The tube’s mirrors—one fully reflective, the other partially reflective—collaborate to form a beam that exits through the partially reflective mirror.

Once outside the tube, the beam is guided to the laser head via lenses and mirrors, which focus it into a narrow, high-intensity stream aimed at the workpiece.

Complementing beam generation and transmission, computer numerical control (CNC) positions and controls the laser, enabling high-precision cutting even for fine features.