Laser-assisted hot embossing of microstructures

Technologies conventionally used to manufacture micro-structured components with geometries below 100 m are injection moulding and hot embossing. Both technologies are mainly limited to polymer materials and require long cycle times since the whole forming tool has to be heated. These drawbacks can be eliminated by using a newly developed laser-assisted hot embossing technology, where high energy density laser radiation is used for a selective and fast heating of the tool and workpiece, respectively. Using a controlled irradiation of the tool surface by high power diode lasers, tool temperatures of more than 500°C can be achieved within seconds. At this temperature even glass and metals can be structured with the new embossing technology. In comparison to other heating technologies like induction heating, materials with low thermal and electrical conductivity like ceramics can also be used for tooling. Transparent tool inserts made of sapphire enable the direct access o f the radiation into the tool onto the die. Experiments were conducted with glass, polymers and metals. As an exemplified process the basics for the hot embossing of glass are described in this article.