Scientists at a laser-technology research center are developing a new scanning head device that would speed up laser welding and cutting of fiber-reinforced plastic materials. At present, there is no effective process control method for laser processing of such

materials, because of variables in online temperature measurement among products of different compositions, densities, etc. Laser Zentrum Hannover e.V. (an industrial R&D body in Hanover, Germany) is teamed with Sensortherm GmbH and Newson nv to commercialize the scanner.

The former is a developer of high-precision digital pyrometers; the latter specializes in precision measuring and control engineering devices.

As described by LZH, the combined scanning head is designed so that the beam path of a t-e processing laser is decoupled from the detection beam path used for temperature measurement. This means it is possible to have spatially flexible and temporally high-resolution measurements during the processing of CFRP material.

Furthermore, it should make it possible to measure any point within or without the laser interaction zone during laser processing.

To achieve this, the research partners decoupled the laser beam path from the path of the high-speed pyrometer. Separate scanner mirrors tuned to the detection wavelength of the pyrometer will guide the measurement beam of the pyrometer.

Accurate online temperature measurement is important for laser processing of CFRP and similar materials. With a combined scanning head, thermally critical areas in the processing geometry can be monitored accurately. This principle would be the basis for active intervention in the process, and its optimization, according to LZH.

In the research effort, LZH is developing the laser processes and process control techniques for welding and cutting of CFRP; Newson nv, a Belgian company, is developing the combined scanning head; and Sensortherm GmbH is adapting a high-speed pyrometer device to work with different wavelength ranges for the proposed application.

In addition, Sensortherm is optimizing this pyrometer for laser transmission welding and for laser cutting and material removal.

Using the combined scanning head will not be limited to laser processing of CFRP, according to LZH; metals or glass might be processed, too.

The two-year R&D effort — A'Quilaco (Advanced online quality and process control for high speed laser machining of composites — started in January and is financially supported by Germany’s Federal Ministry for Economic Affairs and Energy (BMWi) and by Belgium’s Agency for Science and Technology Research (IWT.)