Laser sources

Laser cutting

When cutting materials using a laser beam, a high concentration of laser beam energy is used.  When the focused laser beam makes contact with the material being cut, the material absorbs it immediately (the absorption coefficient, or reflectivity, depends on the wavelength of the laser radiation and material type), the material melts from the Joule heat, it is sublimated and a steam-gas channel is formed.  The molten metal residues are removed from the cutting gap by a working gas flowing through a cutting nozzle that is coaxial to the axis of the laser beam.

In the area of laser cutting, we cooperate with the following companies:

What is a laser

A laser is a device that serves as an amplifier of electromagnetic radiation. This radiation may or may not have a visible light frequency. The laser emits very strong radiation with specific properties. Firstly, the radiation is monochromatic, i.e. the radiation has a single frequency. This means that it is a monochromatic light when the light is visible - unlike ordinary light, which is a mix of all the colours. Monochromatic radiation is time-coherent. Another important property of monochromatic radiation is its spatial coherence, which makes it possible to transmit the radiation emitted by the laser in a thin, undisturbed beam and focus it on a small point.

How does laser cutting work

A laser consists of three basic parts: a source of energy, an active medium and an optical resonator. The source of energy is sometimes called a "pump". Its task is to deliver energy to the active medium so that it can get into an excited state. The source is most often either electric or light-based (e.g. a gas-discharge lamp), but there are other laser types as well. The medium needs to be supplied with an amount of energy that causes the number of particles in an excited state to be higher than the number of particles in the basic state. The particle gets into the excited state by absorbing an amount of energy that causes one of its electrons to jump to a higher energy level, which is further away from the nucleus.

When this excited electron jumps back after some time, the same amount of energy is emitted in the form of incoherent radiation. This is called spontaneous emission. The medium is stored in an optical resonator consisting of two curved mirrors, one of which is partially permeable. Radiation generated by spontaneous emission that has the correct wavelength, direction and phase is reflected back and forth from the medium and interacts with the excited particles of the medium each time it passes and causes them to return to the basic energy level.

During such a stimulated drop to the original energy level, the particles emit photons with the same phase, frequency, polarization and direction as the photons of the passing beam, which causes the required radiation to be amplified. A part of the radiation escapes through the partially-permeable mirror in the form of a focused laser beam, and a part is reflected back for further amplification.

Laser types

Depending on the type of active medium used, we distinguish between solid, liquid, gas, plasma and semiconductor lasers. In industry, ruby lasers, YAG lasers (yttrium-aluminium garnet) or so-called fibre lasers are used, where the active medium is an optical fibre. In gas lasers, mainly CO2 is used. In addition to those, semiconductor lasers (or so-called diode lasers) are distinguished. According to the time mode, we divide lasers into continuous and pulsed lasers, which emit radiation in flashes that sometimes last no longer than one millionth of a second. The beam generally flows from the source to the working head through optical fibres.

Laser applications

The function of lasers in industry is to create a beam of radiation and bring it to the necessary spot, where it can heat the material being worked with. According to the parameters of this process, the laser can be used for making inscriptions on the material, welding or cutting. During the cutting process, the material melts and evaporates, or it is carried away by a stream of gas or burns away. The cutting surface is very high-quality. The laser is suitable for cutting materials with a thickness of up to 10-15 mm, especially soft steel, steel alloys, and aluminium and its alloys. The cutting process is highly efficient and accurate - it is computer-controlled. Due to the very small diameter of the beam, the heat-affected area is also minimal. Its disadvantage compared to other cutting technologies is its higher economic and operational demands.