Laser joining of metals

The number of applications for laser beam welding in industry continues to grow. The specific advantages of laser welding in comparison to conventional welding techniques are the low energy per section (little distortion of components), the opportunities opened by deep penetration welding (overlap joints) and the broader spectrum of weldable materials.

Within the scope of public-funded research projects and research projects for industry extensive results about metal welding have been obtained.

For the automotive industry in particular, joining processes for numerous applications, such as car bodies and functional elements but also gear wheels, wheel rims, shift-forks and accumulators, have been developed. By means of an appropriate process management even steel with a high carbon content can be welded free of cracks. The forming characteristics can be guaranteed by means of a downstream or integrated local thermal treatment.

For welding applications with higher demands on the gap bridging ability, MIG hybrid welding is being qualified for sheet steel and magnesium. Filler material is molten by the arc and can be added without negative effects on the welding speed.

In the field of light metals many applications for aluminium have been implemented in industry. LZH carried out investigations on laser beam welding of aluminium cast and extrusion materials; the results were used for the development of aluminium car bodies. Even difficult-to-weld alloys can be welded by modern high-power lasers. Metallurgical restraints, such as the high hot brittleness of certain alloys, can be overcome by means of a customized process technique and the controlled use of filler material.

Future-oriented investigations are currently focused on magnesium and titanium alloys. The use of these light metals is of great importance to both the transportation and medical technology.

Besides welding and metallurgy-relevant developments, LZH develops process-technical solutions consisting of customized system technology, processing heads and clamping tools.

Laser brazing can be used for various metals that are not weldable due to their composition or for joining processes where the thermal exposure of the parts should be reduced. In many cases, a bonded joint of metals that are not of the same kind can only be generated using laser brazing.

In addition, laser brazed seams fulfil high optical demands on the seams. Besides the joining of ceramics and metals, laser brazing of carbide metal cutting edges of buzz saw blades or the manufacturing of tailored hybrid blanks made of steel and aluminium using laser brazing were investigated within the scope of public-funded projects, too.

Numerous laser brazing processes for components for the automobile technology, motive power engineering, medical technology and electronics were qualified in line with industry projects.