Dense P/M Component Produced by Solid Freeform Fabrication (SFF)

Abstract

Using fine metal powders, we were able to fabricate dense P/M (powder metallurgy) products by a three-dimensional inkjet printing system. We used carbonyl nickel powder with a mean particle size of 5 mm as a raw material and examined two binder supply methods: (i) supplying a binder directly from the inkjet head (DB method), and (ii) coating the powder with a water-soluble polymer and then supplying thin polymer-dissolved water from the inkjet head (CB method). The layered green product was sintered in a hydrogen atmosphere at a temperature in the range of 1073–1623 K. Sintered samples fabricated by the CB method had non-uniform microstructure due to agglomeration of the coated powder. In samples made by the DB method, the macroscopic shape was retained after high-temperature sintering at 1623 K, and a high density of over 90% was achieved, which was attributed to uniform powder cohesion in the laminating process.