Effect of milling parameters on HSLA steel parts produced by Wire and Arc Additive Manufacturing (WAAM)

Additive manufacturing is considered a motivator for the development of the industrial world. Recent advances show that Wire and Arc Additive Manufacturing (WAAM) has the potential to become a relevant method for the fabrication of large complex-shaped metallic components. In this study, we address one of the most important post-processing methods for WAAM parts to be used in structural applications, milling. In this work, thin-walled high strength low alloy steel parts were manufactured by WAAM and their micro-structure was characterized. Then, a milling strategy which considered the microstructure and local mechanical properties of each part was employed. The results show that the mechanical behavior of the as-built parts does not yield a significant influence on the milling process. Overall, it was ascertained that the quality of the milled surfaces improves, that is, has lower roughness, with the increase of cutting speed and with the decrease of feed per tooth. Nevertheless, we highlight the need for more attention to be dedicated on post-process machining operations after WAAM, to establish the best strategies aiming at decreasing tool wear, while maintaining both high surface quality and production rates.