Laser cutting uses a focused beam of light to melt, burn, or vaporize material along a precise path, guided by a digital design file. Whether you’re working with a desktop diode machine or a full-size CO2 laser, the core workflow is the same: create a vector design, choose the right settings for your material, and let the laser trace your cuts. Here’s how each step works in practice.
Choose the Right Laser for Your Material
The three main laser types each excel with different materials, and picking the wrong one means poor cuts or no cuts at all.
CO2 lasers are the most versatile for non-metal materials. They cut and engrave wood, acrylic, textiles, leather, and glass cleanly and come in a wide range of power levels. If you’re cutting sheet goods or fabric, this is the standard workhorse in makerspaces and small workshops.
Diode lasers are the most affordable entry point. Desktop models typically run around 10 to 20 watts of optical power and can cut plywood up to about 3 to 6mm thick, though thinner stock (3mm or less) requires multiple passes even at higher power. They also engrave metals and plastics, making them popular for hobbyists and small businesses working with simple projects.
Fiber lasers are built for metal. Their beam intensity can reach up to 100 times that of a CO2 laser, which makes them ideal for engraving and marking steel, brass, titanium, and aluminum. They’re primarily industrial machines and overkill for wood or acrylic work.
Prepare Your Design File
Laser cutters follow vector paths, so your design needs to be a clean outline of the parts you want to cut. The most common file formats are DXF, SVG, and AI. Of these, DXF files exported from CAD software tend to be the most reliable because they contain only geometry the machine can interpret.
If you’re working in a design tool like Inkscape or Illustrator and exporting an SVG or AI file, strip out everything that isn’t a part edge. That means removing embedded images, text blocks, dimension callouts, and tables. Your file should contain only lines, curves, circles, and splines that define where the laser needs to travel. You can include multiple parts and different quantities of each in a single file.
Most laser software uses layer colors to distinguish between operations. A common convention is red lines for cuts, blue for engraving, and black for raster fills, though the exact mapping depends on your machine’s software. Separating your operations by color lets you assign different power and speed settings to each layer in one job.
Dial In Power, Speed, and Frequency
Three settings control the quality of every laser cut: power, speed, and pulse frequency. Getting these right for your specific material is the difference between a clean edge and a charred, melted, or incomplete cut.
Power is the intensity of the beam, set as a percentage of maximum output. Higher power cuts deeper but generates more heat. Speed is how fast the laser head moves along the cut path. Slower speeds deliver more energy per millimeter, so thicker materials need slower passes. These two settings work as a pair: if you increase speed, you typically need to increase power to compensate, and vice versa.
Frequency (sometimes called PPI or pulse rate) controls how many laser pulses fire per second, typically adjustable from 1,000 to 60,000 Hz on a CO2 machine. Higher frequency means more pulses hitting the material, which delivers more thermal energy. This matters more than many beginners realize. Cutting paper requires low frequency (fewer pulses, less heat) to avoid scorching. Acrylic needs higher frequency, around 5,000 to 20,000 Hz, to produce a smooth, polished edge. Wood generally cuts best at a low frequency like 1,000 Hz, which produces the brightest, cleanest edge with minimal charring.
Every machine and material combination is slightly different, so always run a small test cut on scrap before committing to a full project. Start with manufacturer-recommended settings, then adjust from there.
Set Up Air Assist
Air assist blows a stream of compressed air through the nozzle directly at the cut point. It serves two purposes: it pushes smoke and debris away from the lens (protecting it from damage), and it clears molten material from the cut path so the beam can penetrate cleanly. It also significantly reduces the risk of flare-ups, especially with wood.
Pressure settings vary by operation. For engraving, you only need enough air to keep the lens clear of debris, roughly 5 to 8 PSI. For cutting wood, MDF, or plywood, experienced users typically run 50 to 60 PSI for the cleanest results. Acrylic is the exception: it cuts best with low air pressure, around 5 to 7 PSI, because too much airflow can cool the cut edge unevenly and create a rough, frosted finish instead of the flame-polished look acrylic is known for.
Even a modest upgrade in air pressure makes a noticeable difference. Side-by-side tests on plywood show that bumping from a small built-in pump (around 4.6 PSI) to a compressor regulated at 15 PSI dramatically improves cut quality and reduces charring.
Materials You Should Never Cut
Some materials release gases that are genuinely dangerous or will destroy your machine. The most important ones to avoid:
- PVC and any plastic containing chlorine: Produces chlorine gas when heated, which is toxic to breathe and corrodes metal components inside the laser.
- Vinyl: Also releases chlorine gas for the same reason.
- Polycarbonate (Lexan): Produces fumes that damage the laser’s optics and internal components, and it cuts poorly anyway, tending to discolor and melt rather than vaporize cleanly.
If you’re unsure whether a plastic is safe, check its recycling code or the manufacturer’s data sheet. When in doubt, don’t cut it. The fumes from a single PVC cut can damage both your lungs and your machine.
Ventilation and Fume Extraction
Every laser cutter needs active ventilation. Even materials that are “safe” to cut, like wood and acrylic, produce smoke and fine particulates you don’t want to inhale. You have two options: vent exhaust outside through ductwork, or use a fume extractor with a filter system.
Airflow requirements depend on your machine’s enclosure size. A mid-size desktop laser like the Universal Laser Systems VLS4.60 specifies 250 CFM at 6 inches of static pressure. Smaller hobby machines need less, but you should still match or exceed the manufacturer’s recommended airflow. The practical rule is to set your extraction to the lowest flow rate that still clears fumes quickly from the cutting area. If you see smoke lingering inside the enclosure during a cut, you need more airflow.
Safety Gear and Eye Protection
Laser light can cause permanent eye damage in a fraction of a second, even from reflections. Enclosed machines with interlocked lids handle this by containing the beam, but if you’re working with an open-frame diode laser or performing any maintenance on a CO2 system with the enclosure open, you need laser safety glasses rated for your specific wavelength.
Safety glasses are rated by Optical Density (OD), which measures how much laser light they block. Each OD number represents a tenfold increase in protection: OD 1 blocks 90% of light, OD 3 blocks 99.9%, OD 5 blocks 99.999%, and OD 7 blocks all but one ten-millionth of the beam’s energy. The ANSI Z136.1 standard requires eyewear to be specified by OD for the laser’s wavelength. Always match your glasses to your laser’s exact wavelength and power, not just any pair labeled “laser safety.”
Beyond eye protection, keep a fire extinguisher within arm’s reach. Laser cutting involves heat and flammable materials, and small flare-ups happen. Never leave a laser cutting job unattended.
Maintain Your Optics
A laser’s beam path typically bounces off one to three mirrors before passing through a focus lens. Over time, smoke residue and dust coat these surfaces, absorbing beam energy and degrading cut quality. Cleaning the lens and mirrors regularly is the single most important maintenance task.
Signs that your beam path needs attention include reduced cutting power, inconsistent results across different areas of the work bed, and shadow lines or double cutting lines on your material. Check alignment every 3 to 6 months, or sooner if you notice any of these symptoms. Always clean the mirrors and lens before adjusting alignment, since a dirty optic can mimic the symptoms of misalignment.
Most machines use a pulse test where you fire the laser onto tape placed over each mirror in sequence, checking that the burn mark is centered. If the mark drifts off-center at different positions on the bed, the mirrors need adjustment. Your machine’s manual will walk you through the specific screws to turn, but the principle is the same across all CO2 systems: start at the first mirror closest to the laser tube and work forward, one mirror at a time.