Manufacturing and properties of metal parts made by fused filament fabrication

A complete process chain for the additive manufacturing of metal components by means of Fused Filament Fabrication (FFF) is being developed in a joint project. The final goal is to develop a process chain that provides ready-to-use parts of industrial quality at moderate investment cost. This includes a 4-axis milling machine for green and final machining of the as-printed and sintered parts and a compact furnace for debinding and sintering. This paper reports about ongoing work in the funded joint project “AMCC Line”. A thermoplastic filament with a high metal powder loading of 55 vol% was developed and successfully processed on commercially available FFF printers. In order to achieve near full density metallic parts, a debinding treatment is required that removes the organic constituents. Subsequently, the individual metal particles are joined by diffusion in the solid state (sintering) and a fully metallic part is obtained. It was possible to print and heat-treat different parts in stainless steel 316L. Examples of achievable geometries and a strategy for dimensional and mechanical property monitoring is presented that provides information about the industrial viability of this process chain