Executive Summary : | The present work focuses on the 3-D printing of large metallic components with overhang structures by wire arc additive manufacturing process (WAAM). The challenge associated with fabrication of overhang structures is mainly the deposition of weld beads. In this process, the overheating of the component reduces the viscosity of molten metal, thereby it flows out of the pool due to the effect of gravity. Hence, the printed component loses the dimensional accuracy. To cope with this issue, a flexible deposition strategy is proposed which will utilise different modes of metal transfer depending on the requirement at different locations of the component. The open-source slicing software (Ultimaker Cura) will slice the CAD model of the 3D component, and the tool path will be generated for each layer. The cold metal transfer (CMT) welding setup will be used to generate the arc, and the robot will control the motion of the arc. The welding setup will be interfaced with the robot to incorporate the welding parameters in the robot programming language. Considering the facts and the available literature, the flexible deposition strategy in 3D printing can make complex shapes with better dimensional accuracy. Also, this technology can be used to repair large structures, especially in the automobile and aerospace industries. |