Solid-State vs. Fusion-Based Metal Additive Manufacturing Technologies

Metal additive manufacturing (M-AM) processes are still seen as non-conventional in the industry, and they are considered for niche applications rather than mass production. The major determinant in the industry is the production time and unit cost. Casting, metal forming, and most machining processes are matured and optimized for low to medium-cost mass production; however, a large portion of manufacturing includes customization and there are also many products that are made only one or in very small quantities, where M-AM processes may be a good alternative to conventional manufacturing. Then, understanding the strengths and weaknesses of M-AM is critical in selecting the most technically and economically feasible option. Classifying the M-AM processes as fusion-based and solid-state is important in the sense that there are significant differences in the material properties and geometric precision provided by each category. Overall, fusion-based technologies yield net-shape parts with material properties close to casting. On the other hand, solid-state processes produce “near-net-shape” geometries; however, material properties may be superior. Nevertheless, almost in all cases, some post-processing including a surface finish operation is required.