A laser cutter opens the door for design and functionality. The precision tool is widely used for metal fabrication, woodcutting, plastic manufacturing, art & décor, and more. How does a laser cutter work? What are the types of laser cutting machines? We’ll answer those questions and more in this article.
What is Laser Cutting?
Laser cutting, like the name suggests, is cutting of a broad range of materials of different thicknesses and sizes using a high-powered laser beam. It is used for trimming down wide range materials including gemstone, paper, wood, glass, plastic, metal, etc. Or, it is used to cut intricate shapes that other custom-designed tools would find challenging.
Laser cutting is a thermal-based, non-contact fabrication process where the laser burns through the metal or non-metal materials. The Computer Numerical Control (CNC) system and laser optics are used to guide the movement of the CNC laser cutting machine to cut or engrave specific shapes and sizes.
Types of Laser Cutting Machines
Laser cutting machines are broadly categorized into three categories: liquid, gas, and solid-state lasers. The most commonly used laser cutters are CO2 lasers and solid-state lasers. CO2 based laser machines can be used for cutting sheet metals but are more suitable for cutting non-metal material and organic materials. Solid-state lasers like crystal and fiber lasers are more suited for cutting metals. Crystal lasers are expensive and have a shorter lifespan, whereas fiber-based lasers are relatively cheaper and long-lasting.
A CNC laser cutting machine is one where the CNC system guides the metal laser cutter on the cutting framework or path. It provides better precision and appearance of the finished product when compared to a manual cutting machine.
There are three major varieties of laser cutting: reactive rutting/flame cutting, melt and blow/fusion cutting, and remote cutting. In flame cutting, the heated metal reacts with oxygen and begins to oxidize by burning, thereby assisting the laser beam. Fusion cutting uses inert gases like nitrogen to blow out the molten material, reducing the required laser power. In the process of remote cutting, there are no assist gases used, as the high-power laser beam on the material enables its easy cutting.
How Does a Laser Cutter Work?
The basic process of laser cutting includes generating the high-power beam, focusing of the beam, localized heating and melting, ejection of materials, and movement of the beam. The generated beam can either be a continuous wave beam or a pulsed beam emitted in short bursts. The process of stimulated emission and spontaneous emission is carried out by the laser resonator to produce a spectrally coherent and spatial beam.
This beam then enters the laser cutting head, and there are mirrors in place that guide the laser light onto the focusing lens. The beam is focused through the center of the nozzle incident to the material’s surface. Focusing helps in increasing the intensity of the beam by concentrating on one small spot. As a result, the localized area of the material absorbs the radiation, heats up, melts, or partially vaporizes.
An assist gas can then be used to expel the melted area out of the kerf. Other material removal mechanisms like chemical degradation cutting, scribing, fusion cutting, or oxidation can also be used to expel the waste material. The beam movement in the machine is achieved either by:
- moving the cutting surface to which the material is affixed
- using flying optics to move the laser beam around the cutting surface
- or by using a hybrid of the two
A CNC laser cutting machine that uses flying optics is preferred as these allow relatively faster processing times and are suited to cut materials with variable sizes and thickness.
When compared to other forms of cutting, metal laser cutting services offer various benefits, including high-quality edges, better operational safety, lower repair and maintenance costs, greater accuracy, and precision. By adding the CNC technology to laser cutting, complicated cutting designs and high-quality cuts can be repeatedly produced, which do not require further finishing or cleaning.