Feasibility study of aluminium deposition by robotic MIG welding process

Among the various processes of additive manufacturing, the wire arc additive manufacturing process (WAAM) is quite attractive due to its high deposition rate. Although the surface finish of WAAM generally requires machining due to its roughness, it is not significant against its productivity and its low costs.

In this study, WAAM is based on the deposition of layer upon layer in which each layer is a bead of metal inert gas (MIG) welding. To make a part, the welder robotic arm was used for torch movement. In recent years, the production of aluminum components with WAAM process is progressively more and more interested by various industries due to its advantages. In most of the past researches, cold metal transfer (CMT) was used for this purpose. However, in this research, the conventional pulsed spray metal transfer mode was utilized in order to study the feasibility of this process. Various welding parameters were applied to create walls with different inclination angles using ER4043 and ER5356 as filler materials and 6061-T6 as substrate. Then, wall quality was investigated in terms of porosity, roughness and effective width. The interaction between layers was also studied in terms of microstructures, grains size and microhardness at different points in the walls. Due to the penetration of heat from the upper layers to the lower layers during the construction of the wall, the isotropy of the microstructure gradually increases in the lower layers. The improvement of the mechanical properties in the lower sections of the wall was also observed by microhardness measurement and tensile tests.