AISI 304 stainless steel engraving by Q-switched Nd:YAG nanosecond laser

Laser deep engraving is one of the most promising technologies used in rapid prototyping to produce tools and moulds. In this method, a laser beam is used to ablate a solid bulk, following predetermined patterns. The tool or mould is obtained by repeating this process on each successive thin layer. The precision degree of the shape and the surface quality during engraving process strictly depend on the laser source characteristics and on the process parameters. The aim of this work is to investigate the influence of the process parameters on the material removal rates and the surface roughness engraving AISI 304 stainless steel using a Q-switched diode pumped Nd:YAG laser. The examined parameters were: pulse frequency, pulse energy, feed rates, distance between the linear patterns of the laser scanning and number of repetitions. The working parameters and the engraving process behaviours were correlated. It was found that high volume removal ratio and high surface quality are difficult to achieve simultaneously. However, an accurate selection of the process parameters allows an increase of the surface quality at the same removal rate.