Modern hybrid machine tools offer both conventional machining and advanced additive manufacturing (AM) processes in a single machine platform, typically using one of two direct-energy deposition AM processes: laser powder deposition or laser hot-wire deposition (HWD). Mazak officials report development of a deposition head by the company that enables creation of complex 3D profiles via HWD that previously proved difficult and cumbersome, providing HWD with one more advantage over laser powder deposition. Laser powder deposition processes, using a laser to sinter a blown powdered feedstock to a substrate, have several benefits: fine net resolution, minimal thermal distortion and creation of parts with custom material properties. But, powdered metal alloys present many environmental health and safety concerns, utilization of expensive feedstock is low - around 85 percent-and not all materials are available in powdered analogs. HWD works by using a high-powered laser to create a melt pool in a substrate. Then, a wire feedstock, preheated using electrical resistance, feeds into the melt pool, flooded by a shielding gas. This process provides good adhesion between layers and creates a homogenous structure in the final part. HWD solves many problems inherent in the powder process, as inexpensive wire feedstock presents few environmental health and safety concerns. Feedstock utilization reaches 99 percent with virtually no material limitations as most alloys are available in a welding-wire analog. And, HWD processes add material at much higher rates than powder. While HWD, unlike powder, cannot mix alloys or produce ultra-fine geometries, machine-tool OEMs still prefer wire AM technology over powder.
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