Laser source independent basic parameters — Focus position, pulse overlap, track overlap — In laser micro milling using as rapid manufacturing process

Abstract

Laser micro machining belongs to the most important processes in rapid prototyping / rapid manufacturing. Especially Nd:YAG lasers with a galvanometer scanner are extremely common in manufacturing Micro-Electro-Mechanical-Systems (MEMS) in a time and cost saving manner. Moreover, laser micro milling is one of the most significant processes in laser micro machining apart from laser micro cutting and micro welding. In recent years a lot of investigations were done for direct parameters of the laser source such as the laser power, the fluence, the repetition rate, the lamp current, and the pulse duration. These parameters are not applicable to other laser systems because they are depending on the used laser source. The basic parameters (focus position, pulse overlap, track overlap), which are completely independent of the used laser sources, were mostly neglected although they have a huge influence on the result of the process. Therefore, this project investigates laser micro milling square pockets in silicon with a nanosecond Nd:YAG IR laser. For each basic parameter the ablation rate, the surface roughness as well as the machining diameter are determined.