A laser cutter is a workshop machine that uses a tightly focused beam of light to cut or engrave materials such as acrylic, wood, cardboard, leather, and some coated metals. In many desktop machines, a CO2 laser creates infrared light that is guided by mirrors and focused by a lens onto the workpiece. The beam delivers energy to a tiny spot, heating the material until it melts, burns, or vaporizes.
Laser cutters matter because they connect digital design to precise physical fabrication with very small kerf and repeatable results.
Inside a typical CO2 laser cutter, the beam travels from the laser tube through alignment mirrors to the moving laser head, where a lens focuses it onto the material surface. The motion system moves the head along toolpaths from a vector file, while the controller adjusts power, speed, and pulses. Air assist blows smoke and debris away from the cut, and exhaust ventilation removes fumes from the enclosure.
Safe operation depends on correct focus, proper material choice, good ventilation, fire monitoring, and using the correct laser safety enclosure.
Key Facts
- Laser energy per unit length increases when power is higher or speed is lower: energy per length = P / v.
- Power in watts is energy per second: P = E / t.
- A focused beam makes a small spot, increasing intensity: intensity = P / A.
- Kerf is the width of material removed by the cut, so final part size must account for it.
- CO2 laser cutters commonly use infrared light with wavelength about 10.6 micrometers.
- Air assist and exhaust reduce flame risk, improve cut quality, and remove hazardous fumes.
Vocabulary
- CO2 laser
- A gas laser that uses carbon dioxide to produce infrared light, often used for cutting and engraving nonmetal materials.
- Kerf
- The narrow width of material removed by a cutting process.
- Focus distance
- The distance between the focusing lens and the material surface where the laser spot is smallest.
- Air assist
- A stream of air directed at the cutting point to clear smoke, cool the surface, and reduce flames.
- Vector cut
- A cut made by following lines or paths from a digital drawing rather than scanning across an area.
Common Mistakes to Avoid
- Using unknown plastic, because some plastics release toxic or corrosive gases when lasered. Always verify the material, and never cut PVC or vinyl in a laser cutter.
- Setting power too high and speed too low, because excess energy can char material, widen the kerf, or start a fire. Start with tested settings and adjust gradually.
- Ignoring focus height, because an unfocused beam spreads out and cuts poorly. Set the correct focus distance before running the job.
- Leaving the machine unattended, because small flames can become dangerous quickly. Watch the entire cut and keep approved fire safety equipment nearby.
Practice Questions
- 1 A laser cutter runs at 40 W and cuts along a path at 20 mm/s. What is the energy delivered per millimeter of path in J/mm?
- 2 A square acrylic part is designed to be 80.0 mm wide, and the laser kerf is 0.20 mm. If the cut line is placed exactly on the outline, about how much smaller will the part be across its width?
- 3 A student wants cleaner cuts in plywood but notices heavy smoke marks and small flames. Explain how changing air assist, speed, power, and focus could improve the cut while reducing risk.