TPT March 2014

Industry News

Cooperation for welding of lightweight structures

construction of components to the process, to adapting the material to the process, to optimising the laser welding process itself. Up to now, for example, adhesives have been used to join fibre reinforced materials, meaning the material surfaces must be intensively prepared, and a drying stage is necessary. An alternative to adhesives is mechanical joining using rivets or screws. However,

LASER Zentrum Hannover (LZH) and seven other partners have completed the ‘LaWocs’ research project. From December 2010 to November 2013, the national and international project partners worked on ‘laser transmission welding of thermoplastic composite structures’. Goals connected with the field of environmental protection are ambitious, and include saving energy by reducing fuel consumption, and reducing CO 2 emissions. This is a challenge for all industrial manufacturers. In order to achieve these goals, new lightweight construction concepts based on using carbon fibre reinforced plastics (CFRP) or glass fibre reinforced plastics (GFRP) are being developed. These materials not only offer a high potential for reducing weight, but also have excellent mechanical properties. The Eurostars LaWocs project was the first research project to investigate laser-based welding of fibre reinforced materials. The goal of the project was to design a project chain frommodifying the

The process operation

rates and high piece rates are possible – important pre-requisites for use in industrial manufacturing. European cooperation made it possible to consider all aspects of the individual processing steps for fibre composite workpieces in one research project. Within the framework of the three-year joint project, new materials were designed that are suitable for laser transmission welding but still maintain good mechanical properties. Additionally, investigations on a better understanding of the welding process for different thermoplastic materials were carried out, and used for the development of the welding parameters.

this requires holes being drilled in the components, which interrupt the flow of forces along the reinforcing fibres. Laser transmission welding of thermoplastic fibre reinforced materials offers advantages that include high flexibility, making it possible to weld complicated geometries. Laser processing is non-tactile, ie forces are not applied to the workpiece, and laser energy can be specifically applied only to places where a welding seam is necessary. Process control can use a non- tactile pyrometer for measuring temperatures, for example to successfully weld thermoplastic GFRP with CFRP. Laser welding of composite materials can be used to simplify production processes. At the same time, this method has a high automation potential, and production with short cycle

Laser welded interior aircraft pins

Laser Zentrum Hannover eV – Germany Fax: +49 511 2788 100 Email: info@lzh.de Website: www.lzh.de

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M arch 2014