Fiber laser vs CO2 laser: metal, non-metal and running costs

Verdict: a fiber laser suits any shop whose cutting is mostly metal: steel, stainless, aluminum, copper and brass. It is faster on thin sheet, uses less electricity and has no mirror path to clean and align. A CO2 laser still suits sign, display and packaging shops cutting acrylic, wood, paper, leather and many plastics.

That is why fiber has become the default for sheet metal, and why CO2 machines have not disappeared. The difference comes down to one property of light, wavelength, and to how the beam gets from the source to the cutting head.

Fiber vs CO2 at a glance

Factor	Fiber laser	CO2 laser
Wavelength	About 1.07 µm	10.6 µm (9.3 to 10.6 µm across CO2 types)
Best materials	Mild steel, stainless, aluminum, copper, brass	Acrylic, wood, paper, leather, many polymers; also metals
Beam delivery	Flexible fiber cable, constant optical path length	Mirrors along an open beam path whose length changes as the head moves
Optical upkeep	Protective windows and nozzles; no mirror alignment	Regular cleaning of the beam path and mirrors, plus alignment
Energy use	Higher wall-plug efficiency	Lower wall-plug efficiency
Thin sheet speed	Much faster	Slower
Thick plate	Gap narrows with thickness; high-power fiber cuts 30 mm mild steel and more	Competitive on thick material, historically its strength
Copper and brass	Handled; ask about back-reflection protection	Higher risk to the optics
Acrylic edge	Poor, non-metals absorb little of the beam	Glossy, polished edge straight off the machine

Wavelength and absorption: the root of the difference

Mitsubishi's MC Machinery gives the fiber wavelength as 1.07 µm and the CO2 wavelength as 10.6 µm, and notes that the shorter wavelength is more readily absorbed into metals, which means higher cutting efficiency. More of the beam goes into melting metal instead of bouncing off it.

The same physics runs in reverse for non-metals. Gweike's technical notes say that wood, acrylic (PMMA), paper, many polymers and leather couple well to the 10.6 µm CO2 wavelength, while non-metals hardly absorb a fiber laser's beam. That is why a fiber laser is the wrong tool for a sign shop's acrylic letters, and why CO2 is famous for leaving a glossy, polished edge on acrylic.

Reflective metals are the other side of the story. Gweike notes that copper and brass pose a higher reflection risk for CO2 optics and that fiber handles them more safely. Fiber sources are not immune either: TRUMPF points out that a laser can be damaged by back reflection when cutting non-ferrous metals and says its own sources are protected against it. When you compare fiber machines for copper or brass work, ask each supplier how its source handles back reflection.

Beam delivery and maintenance

A CO2 cutting machine carries its beam from the resonator to the head through a series of mirrors. As the head moves across the sheet, the path length changes, so machines use adaptive optics to keep the focus consistent, as MC Machinery explains. The mirrors need regular care: Gweike lists weekly cleaning of the beam path and the reflecting and focusing mirrors among CO2 routines. Sealed-tube CO2 lasers also slowly lose their laser gas, and Gweike puts the tube replacement interval at about one to two years. MC Machinery adds that temperature and optics ageing gradually reduce the power and cut quality of a CO2 system.

A fiber laser generates its beam inside a doped optical fiber and delivers it to the head through a flexible cable. The optical path length never changes, no matter where the head is on the table. There are no mirrors to align. Day-to-day optical upkeep comes down to protective windows and nozzles at the head, which is one reason fiber machines suit shops without a dedicated laser technician.

Efficiency and your electrical service

Every source in this comparison agrees that fiber converts more electricity into laser light, though the figures differ with who is counting and what is included (source only, or source plus chiller). MC Machinery cites energy savings of up to 30 percent in wall-plug efficiency, and Gweike describes fiber machines as about three to four times more efficient than CO2.

Whatever the exact figure, the practical results are the same: a smaller electrical service for the same cutting power, less heat for the chiller to remove and less waste heat in the building. For imported machines this ties into supply voltage as well; our guide to 600 V power for imported machines explains transformers and what to check before the machine arrives.

Speed and thickness

Gweike puts fiber's general cutting speed at about three times that of CO2, with the gap closing as material gets thicker. Fiber is strongest on thin and mid-thickness stainless and mild steel. Cut with nitrogen, it gives bright, oxide-free edges that are usually ready for welding or paint with little preparation. Oxygen cutting leaves an oxide layer, a trade-off explained in our assist gas guide.

Thick plate used to be CO2's clear advantage, but power has closed the gap. TRUMPF rates its enclosed TruLaser 1030 fiber with a 12 kW source for 30 mm mild steel, or 40 mm with its thick-sheet package, and 40 mm stainless. Choosing the right power for your thickness range is covered in our fiber laser power guide.

Why fiber took over sheet metal

• Absorption: metals take in more of the 1 µm beam, so more of the power does useful work.
• Beam delivery: a fiber cable replaces the mirror path, removing alignment work and a source of drift.
• Energy: higher wall-plug efficiency means less electricity per part and a smaller chiller.
• Speed on thin sheet: the bulk of sheet metal work is thin to medium gauge, exactly where fiber is fastest.
• Reflective metals: aluminum, copper and brass jobs became routine instead of risky.

The result is visible in any catalog of new sheet cutters: machines like the Mazak OPTIPLEX 3015 NEO, the Amada ENSIS-3015RIe and the compact Gweike LF1390 for small precise parts are all fiber machines. You can compare every model on our fiber laser category page.

Where CO2 still wins

• Non-metals: acrylic, wood, paper, leather and many plastics. TRUMPF says its CO2 lasers can also process corroded and damp surfaces, plastics, composites and organic materials.
• Acrylic signage and displays: the polished edge is the product, and fiber cannot deliver it.
• Mixed-material shops: where metal is a minority of the work, a CO2 machine covers more of the job list.
• A paid-off machine in good condition: an existing CO2 laser still cuts good parts. Replacing it is a cost and capacity decision, not a necessity.

For sheet plastics and wood, a CO2 laser is not the only option. Many sign and display shops cut acrylic, composite panels and wood on a CNC router, such as the AXYZ INFINITE 4000, which cuts these materials mechanically with a spindle rather than with a beam.

How to decide

List your last year of work by material. If metal is most of the cutting hours, fiber is the default and the real questions are power, bed size and automation. If acrylic, wood or other non-metals are a large share, keep or add CO2 or a router for that work and consider fiber for the metal. If you run a CO2 machine today, compare electricity, maintenance hours and cycle times on your own parts before deciding when to replace it.