Solid freeform fabrication of metal components using fused deposition of metals

A new hard tooling fabrication technique, named fused deposition of metals (FDMet), to fabricate prototype metal components was investigated. This fabrication is performed directly from a computer-aided design (CAD) file without using molds, dies, or similar tooling. The FDMet process is based on a patented fused deposition modeling (FDM) and fused deposition of ceramics process where a three-dimensional (3D) object is built from a 1.75-mm diameter metal filament fed into a heated extruder head capable of moving in the X-Y direction. The head extrudes controlled and continuous flow of material onto a fixtureless platform capable of moving in the Z-direction. The process from raw material to the final prototype is described. The post processing steps include binder removal of the polymer in the green part and sintering to densify the part. To demonstrate the capability of this technique, several standard samples and hard tooling components such as a wrench and lug fit were fabricated. The accuracy and reproducibility issues are discussed.