Different build strategies and computer-aided process planning for fabricating a functional component through hybrid-friction stir additive manufacturing

Abstract

ABSTRACT Hybrid Additive Manufacturing (HAM) technologies leverage the strength of Additive Manufacturing (AM) and Subtractive Manufacturing (SM) in fabricating complex geometries with precision. Friction Stir Welding (FSW) has been acknowledged for joining sheets of similar or dissimilar materials with improved mechanical/metallurgical properties. However, due to the inherent pinhole defect and complicated toolpath planning, this process has not been explored much for fabricating the objects in a layer-by-layer manner. Therefore, this work investigates Computer Aided Process Planning (CAPP) for realizing fully functional metallic parts through a HAM system. This HAM system uses a Sheet Lamination (SL) process, i.e. Friction Stir Additive Manufacturing (FSAM), synergistically coupled with an SM process, i.e. machining. To realize complicated geometries through the proposed HAM system, three different build strategies are developed viz. Near-net block fabrication, Near-net shape fabrication via ‘form-then-bond approach’ and ‘bond-then-form approach.’ Each build strategy consists of a detailed CAPP that includes toolpath planning, tooling aspects, simulated outcome and so on. Further, these build strategies are discussed for realizing the parts with Functionally Graded Materials (FGM) & embedded structures. Finally, a monolithic object of aluminium has been fabricated as a case study to demonstrate one of the aforementioned build strategies.