Key Advantages of Laser-based Sheet Metal Cutting over Plasma Cutting

Plasma cutting and laser cutting are two methods used to cut sheet metal. Plasma cutting was developed in the 1950s as an alternative to flame cutting. It works by firing a superheated, electrically ionized gas at high speed toward the workpiece. An electrical arc is formed within the gas, ionizing some of the gas and creating an electrically conductive channel of plasma. The electricity from the cutter torch travels down this plasma, generating heat to melt through the workpiece. The plasma and compressed gas blow away the hot molten metal, separating the workpiece. 

Laser cutting was developed in the 1960s to cut holes in diamond dies. This thermal cutting process uses a computer-directed, high-power laser along with oxygen, nitrogen, and compressed air to burn, melt, vaporize or blow away the material being cut. The laser beam is emitted from the laser source and transported through a beamline into the laser head containing lenses that focus the beam onto the surface of the material. 

Two types of lasers are used in these applications: CO2 lasers and solid-state lasers – Fiber Lasers are a specific type of Solid-State lasers.  CO2 lasers are thought to be cheaper but cannot cut through copper, brass, and aluminum because they do not work on reflective surfaces.   In contrast, fiber lasers have higher energy efficiency and can cut a wider variety of materials at higher processing speeds. 

Each method has its own capabilities and benefits. Laser cutting is a non-contact process that offers high precision while plasma cutting offers versatility across different types of metal. Key differences between laser and plasma cutting include cutting technology, precision, capital investment required, cutting speed, cutting thickness, and versatility. 

Fiber lasers advantage over Plasma Cutting 

Fiber laser cutting has several advantages over plasma cutting. It can be used on a wide range of materials, including steel, aluminum, stainless steel, non-ferrous metal sheets, plastics, glass, wood, and ceramics. The bundled laser beam only heats up the material locally, minimizing thermal stresses on the rest of the workpiece. This allows for the smooth cutting of intricate contours with little-to-no burrs. Ultrashort pulses can vaporize virtually any material quickly, creating high-quality cutting edges without ejecting melted material. This makes fiber lasers ideal for manufacturing intricate metal products such as stents for medical technology and cutting chemically hardened glass for the display industry. 

The first commercial laser devices appeared in the late 1980s and used single-mode diode pumping to emit only a few tens of milliwatts. However, many laser applications required watts of optical power rather than milliwatts. The jump to watt-level fiber-laser output was made with the introduction of a 4 W erbium-doped fiber laser. This laid the groundwork for the development of high-power fiber lasers in the 1990s. 

In the early 2000s, fiber laser cutting was introduced to the commercial market. The first fiber lasers for cutting reflective metals were introduced in 2008 and different laser beam conveying methods allowed cutting metals such as aluminum, brass, copper, and galvanized steel.