Lasers for economic and fast etching processes
With the advent of micro-technologies, there is an ever-increasing need to develop advanced technologies and processes in the field of micro-fabrication. Particularly the fabrication of extremely precise micro-parts has so far been very expensive to implement because it is still related to extremely costly equipment. For this reason, micro-fabrication technologies are currently adopted for large-scale developments of various microelectro-mechanical systems, such as sensors and actuators, or integrated optics applications. To address this problem, this EC-funded project focused on chemical etching techniques that are widely used by many industries because of their key advantages. These include excellent precision, repeatability, low cost and lead to processed materials of advanced properties that are extremely durable and reliable. Thereby, the project resulted in a liquid phase etching cell and a process for laser thermo-mechanical surface treatment of metals and metallic alloys. The developed liquid phase etching cell consists of a nozzle assembly and a basin that are connected to each other using elastomer bellows. Without allowing etch liquid intersecting with the laser beam, the cell may be used for both reactive or non-reactive liquids in cases of co-axial injection. Offering constant flow rates over large processing areas, efficient mass transport and cooling, it can be applied in laser processing for enhanced quality and reproducibility. Employing the novel etching cell with the use of newly developed advanced liquids, the laser-assisted chemical etching process may be significantly optimised. This was proven by using a Nd:YAG laser for machining temperature sensitive superelastic NiTi alloys, whereby the processed material exhibited substantially enhanced properties, including surface roughness. This economical and precise process has the potential to become the viable technical solution to challenging problems in many different industries, even for small series production.
