Assessment and implementation of active cooling systems with forced air and half-immersion in liquid in wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) is a notable process in metal additive manufacturing (MAM) for the fabrication of metal parts that utilizes economically viable equipment and has high productivity compared to other MAM processes. However, excessive heat accumulation during metal deposition and the cooling method can induce residual tensile stresses and the emergence of defects, which can compromise the geometrical and mechanical integrity of components produced by WAAM. A relatively effective solution to reduce the occurrence of defects and increase the production of high-quality, structurally reliable parts with better surface finishes is to implement temperature control between passes in the WAAM process. This work is aimed at implementing and evaluating active cooling techniques using forced air cooling system (FACS) and half-immersion cooling system (HICS) in WAAM. For this purpose, FACS and HICS systems were implemented and WAAM preforms were produced under different cooling conditions. Visual inspection and geometric and microhardness characterization of the obtained preforms were performed, as well as productivity analysis of the system. The results of the geometric evaluation show little discrepancy between the dimensions of the preforms produced with different cooling techniques, with significant reductions in manufacturing time using FACS and HICS compared to natural cooling (NC), by approximately 73.1% and 87.1%, respectively. Similarly, the impact of the cooling mode on the formation of porosities is discernible. When the FACS system is employed, these defects are more susceptible to generation. The transverse hardness profiles of the three preforms exhibited comparable trends along the manufacturing direction. However, the manufactured system used by HICS exhibited higher average hardness values.