CNC Laser Cutting Basics: Understanding How it Works

Blog | March 26th, 2021

A laser is a device that can emit light by the process of optical amplification. What makes this device different from other types of light is that it can effectively shoot a light on a tight spot. Even at a distance, the light shot by the laser can stay narrow throughout its application.

One notable application of laser is cutting particularly computer numerical control (CNC) laser cutting. CNC laser cutting is a fabrication process that utilises a laser beam to cut or engrave a material in a precise manner. With the help of computer software, CNC laser cutting can easily burn, melt, or vaporise certain parts of a material. Some of the materials that can be processed with CNC laser cutting include metal, plastic, wood, paper, gemstone, and glass.

CNC laser cutting has numerous stages that fabricators must perform. Some of the most common stages of the CNC laser cutting process are as follows:

Beam Generation

One part of CNC laser cutting that is integral to the process is the laser resonator. A laser resonator is comprised of highly reflective dielectric mirrors that can effectively sustain the laser light and prevent it from escaping. This part can carry out the procedures of spontaneous emission and stimulated emission, helping the laser cutting machine produce a spatially and spectrally coherent laser beam. Spontaneous emission helps in emitting a photon of light, while stimulated emission stimulates a high-energy photon. These emissions all help in generating and amplifying laser beams as they enter the laser cutting head.

Beam Concentration

The focusing lens on laser cutting machines can effectively concentrate the laser beam right into the surface of a workpiece. The laser beam is guided through at the end of the laser cutting head by maintaining its generation to the centre of the nozzle. Keeping the generation of the laser beam on the said medium can direct it to a smaller spot and reduce its cross-sectional area and radius. The concentration of the beam by the focusing lens can likewise increase its overall intensity.

Localised Heating

As the beam travels to the workpiece, the latter can directly absorb the radiation. The beam can afterwards generate heat, which can melt or vaporise a localised area of a workpiece. Once certain areas are weakened and removed, the workpiece can now form the desired cuts and fabrication results. The entire process of localised heating is guided by the cutting or assist gas. This specific gas protects and cools the focusing lens, removes melted material out of the kerf, and supports the cutting process. Some types of laser cutting process include fusion cutting, evaporative cutting, and oxidation cutting.

Beam Movement

Once the localised heating is being conducted, the CNC laser cutting machine will start to move to produce the desired cut. There are several configurations for beam movement: moving material, flying optics, and hybrid laser cutting. Moving material entails the movement of the workpiece around a stationary beam. Flying optics, alternatively, have a movable laser cutter head that can move around a stationary workpiece. Hybrid combines the principles of moving material and flying optics machines.

To learn more about CNC laser cutting, just give us a call at McKean’s Sheetmetal Fabricators.


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