In modern manufacturing industry, lasers have become an indispensable high-tech tool. There are constantly emerging new applications because laser cutting is hard to beat in terms of precision. Especially in sheet metal processing, innovative fiber lasers have gained in importance as an economical cutting process. With this process, plate-shaped materials and 3D bodies such as tubes or profiles can be cut with high precision and free from burrs. For most materials, there is no need for expensive, mechanical post-processing. Depending on the requirements and material, different laser types with corresponding processes are used. In this article, we explain the most common lasers and procedures.
What is laser cutting?
Laser cutting is a cutting process and enables non-contact processing of almost all material groups as well as a wide variety of cutting tasks at the highest quality level. No matter if plate-shaped materials or three-dimensional geometry, the laser enables micrometer-precise cutting in and of metal, plastic, paper, or even rock. The development of innovative fiber lasers has made laser cutting the most cost-effective cutting method, especially in the field of fine sheet metal processing. A wide variety of contours can be produced at high cutting speeds, usually without post-processing. Typical applications are for example the production of technical laser blanks, covers, circular blanks, and the machining of tubes.
What laser cutting processes are there?
Depending on material, application and mode of action of the lasers used, different procedures can be applied.
- Laser jet cutting
This process offers high cutting quality and is extremely precise. In this process, the laser beam melts the material along the contour to be cut, and the resulting melt is blown out with a gas jet under high pressure. The energy of the laser beam can be supplied with pinpoint accuracy, an unwanted oxide formation can be avoided. - 2D laser cutting
This process is the ideal manufacturing solution for plate-shaped materials, as almost all material groups can be processed quickly and cost-effectively. Another advantage of this technology with regard to conventional processes like punching is that it is also possible to produce smaller quantities with high quality and at low cost. - Laser beam gas cutting
This procedure is similar to jet cutting and is usually used for cutting thick material. The only difference is that pure oxygen is blown onto the cutting point. It reacts with the material, generating high thermal energy. Material is cut punctually, and the melt is blown out of the kerf. - 3D laser processing
If complex 3D geometries have to be manufactured with absolute dimensional accuracy, go for this process. It happens on the basis of laser cutting machines which also allow combined laser-punching machining in a single operation. Typical applications can be three-dimensional apertures or body shells. - Laser sublimation cutting:
Material is vaporized with a laser beam under very high heat dissipation. This process is called sublimation, a formation of material melt is prevented, and the entrained gas jet is not used to blow out the kerf but to protect the sensitive lenses and mirrors. A typical example: the cutting of plastics with clear cut edges. - Tube laser cutting
This procedure is performed on laser cutting machines that combine several methods of tube and profile processing in a single procedure. Thus, not only round but also square, rectangular, or oval tubes can be processed with dimensional accuracy. In the same step, contours can be introduced.
How are lasers constructed and what types of lasers are there?
A laser beam is extremely concentrated light. The word laser is short for Light Amplification by Stimulated Emission of Radiation. A laser therefore is a device that produces a coherent light through optical amplification. These cutting systems are all equipped with the same basic components and are available in various designs: as gas lasers, fiber lasers, solid-state lasers, dye lasers, diode lasers, or excimer lasers.
How does laser technology work?
Modern laser cutting machines are extremely powerful, they can be used to process almost all sheet metal formats, material thicknesses, tubes, and profiles made of a wide range of materials. The most important system components are the laser source, the laser beam guidance, and focusing lens with cutting nozzle. Most laser systems are modular in design and can be quickly and easily upgraded with additional modules in no time, for example with automated parts disposal. When it comes to fiber lasers or disk lasers, the laser beams are guided via an optical fiber cable, in the case of CO2 lasers, the beams are guided via a mirror system to the starting point with pinpoint accuracy and then bundled into a powerful laser beam thanks to focusing optics. There are also combined laser-punching machines: punching and lasering are possible in a single operation without exchanging tools.
Wie funktioniert die Lasertechnik?
The most important components of a laser are the laser beam source, the laser beam guidance, and the processing head (focusing optics) including a cutting nozzle. The laser beam can be guided in the near-infrared range (fiber laser or disk laser) via fiber optic cables or via deflection mirrors (CO2 laser) to the processing point.
All laser technology systems are equipped with a pump source, a laser medium, and a resonator. They all work according to the same principle. An external energy is supplied to the laser medium via the pump source and converted into radiation. Both the wavelength of the laser beam and the power density of the laser depend on the resonator, which is located inside the laser. The resonator amplifies the radiation and emits it via a semi-transparent mirror as a focused laser beam. The laser is a versatile high-tech tool and therefore suitable for cutting, welding, drilling, or marking. The advantages of this innovative technology are particularly evident in laser cutting.
A bundled laser beam generated by means of gas (gas laser) or crystal (solid-state laser) is the cutting tool. This intense laser beam is amplified by a lens system and focused with pinpoint accuracy on a tiny area of the workpiece where it produces a high energy density. The material melts or vaporizes: the cutting process along the part contour begins. The removed material is blown out of the kerf by a gas jet that exits the nozzle together with the laser beam.
Advantages and applications of laser cutting technology?
The laser is a very versatile tool and can cut different materials of different thicknesses. In laser cutting, the cutting gap is very narrow, and the quality of cutting is extremely high. Depending on the system, all materials can be cut. Depending on material and process, a clean, narrow and often post-processing-free cut edge can be achieved. Laser cutting offers high material utilization and is therefore very economical. Often, engraving, marking and cutting can be done by the same beam source and within the same procedure.
Which materials can be cut with laser?
Laser cutting is a non-contact cutting process for metallic and non-metallic materials like metal, plastics, glass, ceramics, wood, or paper. A laser is very versatile and is able to cut plate-shaped or three-dimensional materials without force effect. Exact tolerances, completely without mechanical post-processing can be achieved.
What cutting widths are possible with laser cutting?
Narrow cut widths of 1.0 mm and accuracies of +/- 0.1 mm/m can be easily achieved. In micromachining, solid-state lasers even allow fine cuts with widths down to 20 µm. The most important factors for the achievable tolerances are material, part geometry, as well as the process used.
What is a laser cut?
The cutting of materials by heating the material using a pulsed or continuous laser beam is called laser cut. The laser’s entire power is focused on one point and is thus able – due to the high heat generation – to melt or vaporize material.
Laser cutting with fiber, other solid-state or CO2 laser?
Each laser system has its own strengths and different application advantages. Working with CO2 is an obsolescent technology, while fiber lasers are gaining more and more influence as technology advances. The advantages of fiber lasers are apparent in regard of speed, reduced operating costs, little to no maintenance costs, long service life, and three to four times greater flow. It’s the wavelength that makes the difference and indicates what type of material can be processed by which laser.
Solid-state lasers are lasers whose active medium consists of a glass or crystal solid (host material). They have a laser beam with high output power, combined with an optimal pulse frequency and pulse duration. They produce a laser beam with a very small focal diameter, making them the ideal choice for permanent markings like serial numbers, bar codes, and data matrix codes on metals. With a solid-state laser, also ultra-short femtosecond pulses can be generated.
If the materials to be cut are rather thick, then opt for CO2 lasers. They deliver faster initial piercing times, faster longitudinal cutting, and smoother surface quality when cutting materials over 5 mm. For applications requiring laser cutting of metals or material processing of stainless steel, you better go for a powerful fiber laser. For other materials, such as plastics and rubber, both laser types are suitable for material processing.
In industry, fiber lasers are currently a complement to CO2 lasers. Due to their special properties, these solid-state lasers are predestined for the thin sheet area. They enable high processing speeds and filigree cutting thanks to small focus diameters. The higher the power of the laser, the thicker material and the faster it can cut. In microsystems technology and medical technology, the use of lasers enables the most innovative applications