Microstructuring with excimer lasers facilitates the processing of precise geometries and defined surface topographies on plastics, ceramics, metals and composite materials. The material removal with quality optimised parameters shows sharp edges and a small thermally influenced zone. In the surrounding area, ablation products deposit on the surface and limit the use of excimer lasers for machining workpieces.
Processing under vacuum and defined gaseous conditions has shown that deposits can be reduced considerably. In order to achieve this, a universal process gas nozzle was developed. The gas nozzle generates a vacuum in the working zone using an external vacuum pump. Processing gas is supplied from a surrounding circular channel, which guarantees a defined gas atmosphere in the working zone. Using special gas kinematics, the vacuum is stable at 0.04 MPa up to a working distance of 5 mm. The long working distance simplifies 2-D material processing and 3-D surface structuring almost without debris on the workpiece surfaces. The working principle of the gas nozzle is explained and samples of debris reduced processing are presented.
Microcutting of ceramics with flexible geometry using a micro machining system is demonstrated for micro impeller wheels with diameters of 100 to 250 μm.