Fused Filament Fabrication (FFF), also known under Stratasys’ trademark name Fused Deposition Modelling (FDM), is a widely used thermoplastic-based additive manufacturing method for the 3D-printing of polymer parts. FFF could be used to shape parts with Powder Injection Moulding (PIM) feedstocks instead of/ or in addition to injection moulding and after debinding and sintering obtain solid parts with complex geometry. Currently used PIM feedstocks do not necessarily meet the requirements of the majority of FFF machines available in the market, which rely on the use of flexible filaments.
In this paper, the specific properties needed by the FFF feedstock materials are discussed. Different feedstocks with powders of 316L steel, NdFeB , strontium ferrite and a mixture of ceramic powders were characterized (viscosity and mechanical properties) and tested regarding the printability using a conventional FFF machine. Out of these experiments the most important requirements for printable PIM feedstocks are deduced.
Additionally an overview of the state-of-the-art of the equipment, respective processing parameters and examples for currently achieved sinter shrinkage; densities and other mechanical properties as well as achievable surface quality are given.