Jul 2, 2015 Off Comments in Laser Cutting by

New silicon laser-beam-steering micromirrors jointly developed by engineers at the Fraunhofer Institute for Silicon Technology ISIT (Itzehoe, Germany) and the Fraunhofer Institute for Material and Beam Technology IWS (Dresden, Germany) are robust enough to handle the high laser powers needed for laser welding and cutting. The flexure-based microelectromechanical systems (MEMS) steering mirrors, which are etched from silicon wafers, can handle powers in the kilowatt range, rather than the few milliwatts of conventional MEMS steering mirrors.

The high-power operation is possible due to a new protective coating developed in the cooperative project, as well as a new type of evacuated mirror mount.

Frequencies to 0.1 MHz
A major advantage of the thin MEMS mirrors is that they can be swiveled back and forth at extremely high speeds, reaching frequencies of up to 0.1 MHz. This allows the laser energy to be distributed on the workpiece much more effectively than with conventional laser systems, whose mirrors operate at only around 1 kHz.

If a beam-steering laser mirror for materials-processing applications swivels slowly, the beam energy cannot be distributed and dosed as effectively at the weld. “By contrast, rapid oscillation of the laser beam allows us to distribute the heat and adjust it to the respective processing task much more effectively,” says Andreas Wetzig, a specialist in the laser ablation and cutting department at Fraunhofer IWS.

Read more: Cleveland Ohio Laser Cutting – Fast silicon micromirrors improve laser cutting and welding