Messer Cutting Systems’ machines offer a range of cutting options, with fiber laser (straight) and fiber laser plasma combination having emerged as the favored choices among businesses.
Because of its small focus spot, laser cutting is known for its high accuracy.
With laser cutting, a laser beam is focused on the material through a nozzle’s hole, heating and melting the material. A cutting gas that flows coaxially through the nozzle removes the molten material.
Three Types of Laser Cutting
There are three types of laser cutting that exist. These are sublimation cutting; flame-cutting, also known as oxygen cutting; and fusion cutting.
With sublimation cutting, a laser beam brings the material to its vaporization point directly in a process that is called sublimation. An inert, or inactive, cutting gas—such as nitrogen, helium, or argon—forces the molten material out of the cut piece part.
During the sublimation cutting process, the material changes directly from the solid to the gaseous state with as little melting as possible. The cutting gas keeps the particles and vapors away from the optical elements.
To vaporize metal requires more energy than to melt it. Thus, sublimation cutting demands significant laser power and is generally slower compared with other cutting processes. This extra energy, however, delivers cuts of very high quality.
Typical materials used in sublimation cutting are wood, plastic, composites, Plexiglas (PMMA), ceramics, cardboard, paper, foam, and other materials without a melting point. Thin metals can also be cut through sublimation cutting.
Flame Cutting & Oxygen Cutting
With flame cutting, also known as oxygen cutting, a material is heated only to its ignition temperature. Oxygen is used as cutting gas so that the material burns and forms a pure stream of oxide that melts through the additional energy from burning. The cutting oxygen then forces the slag out of the cut piece part.
Typical materials used in flame cutting, or oxygen cutting / Oxyfuel, are low-alloy steel, also referred to as mild steel stainless or aluminum, and cast irons.
With flame cutting, the material’s ignition temperature must be below the melting point. With high-alloyed steels and nonferrous metals, flame-cutting with oxygen is feasible but, for qualitative and economic reasons, it is not ideal.
With fusion cutting, the material is heated by the laser beam up to the melting point and forced out of the kerf by a high-pressure stream of cutting gas (up to 25 bar). As with sublimation cutting, an inert gas, usually nitrogen, is used to force the molten material out of the cut.
In special cases, argon is the inert gas that is used. This is the case, for example, with magnesium, tantalum, titanium, and zircon because these materials form chemical bonds with nitrogen.
Materials that are unsuitable for flame cutting are cut using the fusion cutting process. Materials that are typically used include alloyed steels, also known as stainless steel.
For quality reasons, fusion cutting can also be utilized to cut unalloyed and low-alloyed steels. This creates oxide-free cutting surfaces, but cutting speeds are considerably slower.
- Plate thickness: 1 mm up to 25 mm.
- Typical: 0.5 mm up to 20 mm.
- Laser light can be well focused ca. 0.2 mm.
- Very high power density (some MW/cm2).
- High to medium cut quality (roughness).
- Metallurgical perfect surfaces (oxidized) or metallically blank surfaces (high pressure inert gas cutting).
- Low heat input.
- Hardening within the area of the heat-affected-zone (HAZ) with hardening.
Whether sublimation cutting, flame-cutting, or fusion cutting is used, because of a laser beam’s narrow focus, the width of the cut, or kerf width, is very small compared with other thermal cutting processes. Thus, minimum material is melted, and the laser energy is used very efficiently. The material’s heat input is relatively low so that even small geometries can be cut.
Additionally, the cut edge is relatively straight, providing very high component accuracy from the cutting process. This means that laser cutting is used in the most diverse areas, especially whenever the high accuracy of the component geometry and cut edge are required. The preferred range for steel sheets is up to a material thickness of 20 millimeters. Under certain circumstances, however, this range can extend up to 25 millimeters.
With laser cutting, fiber laser (straight), fiber laser plasma combination, and CO2 lasers are typically used. With greater material thicknesses, however, laser cutting makes sense for only special applications, more usually other cutting processes (oxyfuel or plasma cutting) are used here.
To gain even more flexibility, laser cutting can be combined with plasma cutting.
The Ultimate Guide
Messer Cutting Systems’ MetalMaster Xcel unitized cutting machine and LaserMat® II are choice laser cutting machines, offering customers high speed and precision accuracy.