Laser Micro Drilling

The drilling of microholes with well-defined geometrics is gaining significance in a great variety of areas throughout industry at large. The applications in this respect are extremely multifarious. Laser drilling by means of a great variety of drilling strategies has also managed to establish itself and replace conventional drilling processes in many areas of industry. The areas of application range from the setting of micro-drillings in throughput flow filters and sieves, via drillings in high performance solar cells, right through to injection jets in the automotive industry. But, also in the case of inkjet printing nozzles, laser techniques are gaining ground, because of the touch-less processing, the precise point dosing of the energy input, the slight heat transmission into the material as well as the precision and the reproducibility of the drilling points. Additional advantages are gained from flexibility in the drilling geometrics. For example, variations can be achieved in the processing strategy of micro-drilling by means of a greater aspect relationship (the ratio between the drilling depth and the drilling diameter), or drilled apertures with defined wall angles.

Dependent on the application and the job in hand, a variety of lasers are employed for the production of micro-drillings. Excimer lasers of the solid-state laser type are used in the UV range for plastics, and solid-state lasers of the visual or infrared spectral range types are used in the metal-working industries.

But, the selection of the right laser is nevertheless insufficient for successful working methods. The appropriate drilling process also plays a decisive role. Well-known drilling techniques for example are percussion drilling or treppaning. Percussion drilling involves impinging repeated pulsed laser beams onto the surface of a material until a drilled hole of the required depth has been obtained. The beam guidance in such a process is static. Dependent on the point of focus, the drilling of a fixed diameter or the variable drilling of geometrics can be achieved. Such processes represent an extremely rapid drilling method, where several hundred or thousand drillings can be obtained per second. However, such processes have their limits when high machining quality or taper-free holes are required.

A particularly large development potential is attached to the usage of novel drilling heads or innovative machining strategies for generating of micro holes with precisely controllable taper in different materials.

Laser Systems for Micro Drilling