Laser cutting is a technology that uses a laser to cut materials. The first laser cuts were made in 1967 as part of a military research project focused on lasers. The whole process of cutting works by directing the output of a high-power laser at the material to be cut by a computer. The material then either melts, burns, vaporises away or is blown away by a jet of gas. It leaves an edge with a high-quality surface finish. Industrial laser cutters are used to cut flat-sheet materials as well as structural and piping materials.
It may be interesting to know that the word LASER is an acronym: Light Amplification by Stimulated Emission of Radiation. As a laser is made up of photons, parts of its energy can be reflected away by materials such as aluminum and copper alloys. These materials are also thermal conductors, meaning they distribute incoming heat more evenly throughout their volume. This requires lasers that are more powerful. For this reason, carbon alloys and stainless steel are popular workpiece materials for laser cutting. They are poor at absorbing heat, so heat is concentrated into the laser's path quite easily.
Laser cutting is a fast, non-contact method for cutting or slitting a wide range of metal and non-metal materials. Unlike plasma cutting, cutting by a laser does not suffer from electrode wear from each hole drilled in the workpiece. This type of cutting is applied for different kinds of materials where complex contours demand precise and force-free processing. Lasers create narrow kerfs and thus achieve high-precision cuts. This method does not show any distortion and in many cases post-processing is not necessary as the component is subject to only little heat input and can mostly be cut dross-free.
When compared to other thermal cutting processes such as plasma or flame cutting, laser cutting utilises a much more focused spot or smaller cutting tool. Therefore, it puts much less heat into the workpiece and removes a narrower path of material. This allows the laser to cut parts that are more precise to a higher tolerance and with less taper on the cut edge. As this type of cutting does not require any hard tooling, it is a very "lean" manufacturing method eliminating the need for tool changeover, tool storage and tool sharpening maintenance.
There are three different cutting processes: flame cutting, fusion cutting and sublimation cutting. While making a decision which process to choose one should consider the cut geometry, cycle time, system technology and, above all, the composition of material. In flame cutting, oxygen is used as the cutting gas. Flame cutting makes it possible to cut at high speeds and handle jobs involving thick plates such as mild steel. Laser fusion cutting typically presupposes using inert gases – nitrogen or argon – for cutting higher alloyed steels and aluminum. The great advantage of this type of laser cutting is that the cut edges are oxide-free and do not require further treatment. In the laser sublimation cutting process the idea is to use the laser to vaporise the material with as little melting as possible. This process is rarely used in sheet metal fabrication.
Laser cutting is the largest industrial application of higher power lasers. It is used in industry in a range of applications from prototyping and smaller batch manufacturing to continuous production line systems. In recent years, the increase in this type of cutting has been dramatic due to its increased flexibility, improvements in accuracy, edge squareness and heat input. It is gradually replacing other, more traditional mechanical processes.