Laser Micro Welding of Aluminum with the Superposition of a Pulsed Diode Laser and a Pulsed Nd:Yag Laser

By Philipp von Witzendorff, Lorenz Gehrmann, Martin Bielenin, Jean-Pierre Bergmann, Stefan Kaierle and Ludger Overmeyer

Pulsed laser welding is applied for welding of thin aluminum sheets when the heat affected zone has to be minimized. The pulsed laser process enables a low and precise heat input because the heat dissipates away in between the laser pulses. Applications are hermetic sealing of electronics or opto-electronics which are not persistent enough to resist high temperatures. Aluminum has a low absorptivity (~ 5 %) for the laser radiation of industrial established YAG laser sources which restricts the process efficiency. In addition, several aluminum alloys have a high tendency to generate hot cracks during welding which is even more severe in pulsed laser welding because the pulsed mode leads to rapid cooling. Continue reading

Laser Cleaning of Carbonaceous Deposits on Combustion Engine Components

By Yingchun Guan, Chih-Hsing Liu, Gnian Cher Lim, Hong Yu Zheng and Ming Hui Hong

Carbonaceous deposits covering the surfaces of combustion engine components are known to cause abrasive wear, leading to increased oil consumption and reduce engine durability as well as performance. Remanufacturing is the process acting on end-of-life products to recover manufacturing standards and specifications. Dr. Yingchun Guan from Singapore Institute of Manufacturing Technology (SIMTech), Agency for Science, Technology and Research (A*STAR), and her co-workers have shown how laser technique may be used to remove stubborn carbonaceous deposits without degradation to substrate component.

Laser processing under normal atmospheric conditions may be considered as an environmentally friendly process where no chemicals were used. It has been demonstrated that micron to sub-micron sized surface particulates, corrosion spots as well as thin contamination layer may be cleanly removed without severe damage to the parent substrate. Typical applications include coating or paint removal, biomedical implants decontamination, artwork and cultural heritage conservation and restoration. Continue reading

Laser Applications in the Automotive Industry

By: Klaus Loeffler

TRUMPF Laser und Systemtechnik GmbH, Ditzingen, Germany

The automotive industry has been a target market for the laser soon after the invention of the laser in 1960. Mass production and flexibility have been the arguments for the laser. The first installations in 1973 all the way to late 1980 have been successful due to the missing industrial ready laser resonators. But the laser has seen a fast development over the years and with it the use of lasers in the automotive industry.

Continue reading

Picosecond Laser 4-Beam Interference Ablation of Metal Films for Microstructuring

By: B. Voisiat, M. Gedvilas, G. Raciukaitis

Laboratory for Applied Research, Center for Physical Science and Technology, Lithuania

Properties of the surface highly depend on its relief. The best example is a lotus leaf with the “self-cleaning”, hydrofobic feature. Micro- and nano-structuring with specific patterns and at localized places is useful to control wettability, lubrication and other properties of the surface. Artificial structures borrowed from the nature are applied in automotive industry as well as in photonics and bio-medical research. A new growing application area is frequency-selective surfaces which are working as a filter for electro-magnetic waves in THz, infrared or visible range depending on the period and the feature size of the fabricated surface. They can be produced by laser- structuring of metal films.

Continue reading