What materials cannot be cut on a laser cutter?

I watch shops gamble with unknown sheets every week. The pain is real—ruined optics, toxic smoke, lost profit. You do not have to learn the hard way.

A laser cutter cannot handle every sheet. PVC, ABS, transparent glass on fiber, and carbon-fiber composites all fight back with fumes, fire, or zero absorption. Know the limits and keep your Kirin Laser—and your team—safe.

Every error costs more than the material saved. Stay with me, and you will leave with a clear plan backed by data and field stories.

Which material should you never cut in the laser cutter?

Hope is not a strategy. A cheap PVC sheet looks harmless—until the beam hits and a green plume curls upward. Never cut chlorinated plastics such as PVC or vinyl. They corrode optics, ruin airflow, and poison lungs in seconds.

Why PVC destroys machines and health

PVC is almost half chlorine by weight. Under a CO₂ beam, it cracks into hydrogen chloride gas that turns into hydrochloric acid¹ when it meets moisture. That acid steams across mirrors, rails, and bellows. I once measured pH 2 condensate dripping from an exhaust duct after a single five-minute test cut.

Reaction chain and damage timeline

Health thresholds vs. real tests

Safe path
Route all PVC work³ to a CNC router or switch the design to PETG or acrylic. If the client insists on vinyl decals, kiss-cut them on a blade plotter and weed by hand. My rule: If it smells like a pool, pull the plug.

Which of the following is not suitable for a laser cutter?

ABS promises glossy parts but delivers sticky chaos. ABS melts, bubbles, and keeps burning after the laser moves away. The mess glues itself to honeycomb beds and coats optics with soot.

Why ABS ignites and pollutes

ABS softens at 105 °C, far below the 1 500 °C laser spot. Butadiene units flash first, releasing oily vapors packed with PAHs⁴. These vapors cool into tar that lines your exhaust. At 180 °C, tar reignites, feeding a duct fire that spreads faster than you can reach the kill switch. I have replaced three scorched ducts this year alone.

Thermal runway profile in 6 mm ABS

Cost comparison: ABS failure vs. safe alternative

Safe path
Shift to cast acrylic⁶ for clear parts or HIPS for opaque shells. Both materials cut clean and odor-free on CO₂ systems. When a design truly demands ABS, route or mill it under vacuum extraction.

%[ABS melt](https://kirinlaser.com/wp-content/uploads/2025/04/3kw-laser-cutting-metal-plate.png"ABS melting under laser")

Is there anything a laser can't cut?

Yes—some materials act like glass to the beam. Transparent glass and clear acrylic ignore fiber lasers. The 1 064 nm wavelength sails through, leaving the sheet unmarked.

Why clear materials are invisible to fiber beams

Most transparent polymers⁷ and silica glass have electronic band gaps far above near-infrared photon energy. No absorption means no heat, no cut. Operators often crank power up, unaware that 4 % of that energy reflects into the fiber’s protective window, seeding micro-cracks.

Comparative absorption coefficients

Photothermal stress map (numerical model)

Safe path
Use a 355 nm UV laser for micro-etching glass or a dedicated glass CO₂ scribe-and-break line for thicker panes. Fiber stays king for metals, painted plastics, and opaque polymers only.

What must you never try and cut on the laser cutters?

Carbon-fiber composites look futuristic, but lasers and CF do not mix. Never cut carbon-fiber reinforced polymer (CFRP) with a standard CO₂ or fiber cutter. You will get delamination, cyanide fumes, and ruined optics.

Why CFRP delaminates and poisons

CFRP⁹ contains two distinct layers: carbon filaments and epoxy. Carbon soaks up energy; epoxy only half soaks it, so the layers heat at different rates. Fibers glow white-hot, epoxy chars, and the bond breaks. Edge strength drops by 60 % on the first pass.

Layer failure observation (cross-section microscopy)

Gas analysis during CFRP cut

Safe path
Dry mill CFRP with coated carbide under full vacuum or water-jet it with an abrasive. If the part must stay dry, use an abrasive jet with plastic guard plates to stop fiber pull-out. Remember: the glossy weave hides an ugly, toxic burn¹⁰.

Conclusion

PVC corrodes, ABS ignites, transparent glass ignores fiber beams, and carbon composites delaminate while releasing cyanide. Each failure has its own chemistry, but the outcome is the same—lost time, damaged hardware, and real danger to people. My prevention checklist is simple: research absorption data, test a thumbnail-sized scrap, and keep a written “no-cut” chart next to every Kirin Laser.¹¹ Follow that, and your cutter will reward you with crisp edges, happy lungs, and a healthy bottom line.