Advanced laser technologies

Technologies that use a laser beam for welding, drilling, cutting or hardening are among the progressive and promising methods that allow manufacturers to increase the value of their products or create new products that cannot be made by different methods. Technological demands make it difficult for small and middle-sized companies to buy such machinery. It's economical benefits are not immediate as it is necessary to improve the process and, especially in case of laser welding, to perform a number of technological tests. These are some of the reasons we are creating a facility at ISI that will also offer state-of-the-art laser technologies in the form of a service.

Advanced high power laser technologies

The principle of laser welding takes advantage of high energy density (approx. 107W/cm2) in the area illuminated by the beam, which results in an immediate evaporation of the material with a minimum heat dissipation into the surrounding area. This process creates a cylindrical hole filled with evaporated metal at a pressure which prevents the liquid metal from closing the hole. If the beam is then moved at an appropriate speed the hole follows the beam and a very narrow but very deep weld can be created. This process does not need to take place in a vacuum – a protective atmosphere is applied to the welded spot to suppress oxidation. If a higher pressure process gas is applied along with the beam, the melted material is blown away, which results in cutting instead of welding. Compared to other welding or cutting methods the use of a laser minimizes the heat impact on the material, therefore minimizing deformation.

A fibre laser is used at ISI. The laser is connected to two application heads for cutting and welding. The cutting head is connected to a robotic arm through its own independent linear axis. This axis uses an integrated feedback system to keep the cutting head at a constant distance from the material, which is one of the most critical requirements in the cutting process. The welding head is equipped with a coaxial camera that allows a direct view of the welding process. The application heads are positioned by a six-axis robotic arm. Additional positioning of the processed part is realized by a two-axis positioning system connected to the robotic arm's control system. The highest possible flexibility is achieved in this manner.

Laser parameters:

• laser output: 2kW
• robotic arm reach: 1.6m
• positioning system load capacity: 250 kg
• maximum weld depth: approx. 5mm
• maximum cut width: approx. 5mm
• process speed: up to 10m/min.

Examples of high power laser use:

• Laser beam lap joint welding of two or more sheets up to a total thickness of 5mm, square butt joint welding up to a total thickness of 5mm, welding of metal sheets, mouldings, profiles and pipes, carbon and stainless steel, titanium and other metals and alloys, welding of materials coated with another metal (usually Zn, Al).
• Laser cutting of metal sheets, mouldings, profiles and pipes up to approx. 5mm thick, carbon and stainless steel, titanium and other metals and alloys, materials coated with another metal (usually Zn, Al) or with a protective foil.
• Laser drilling of metallic and ceramic materials shows a high width/depth ratio (up to 1:30) when the laser is operated in a pulsed regime.
• Very small area hardening of materials capable of producing martensitic structure up to approx. 1 mm in depth.
• Technological and prototype testing.
• Welding process research aiming at diagnostics and active control of the process and also the study of the weldability of materials.

Contact:
Ing. Petr jedlička, Ph.D.
e-mail: jedla@isibrno.cz
phone: +420 541 514 327

RNDr. Libor Mrňa, Ph.D.
e-mail: mrna@isibrno.cz

Detailed information: http://www.isibrno.cz

• Login