Bottom‐Up Design of Composite Supraparticles for Powder‐Based Additive Manufacturing. Issue 30 (23rd June 2020) - Canziani, Herbert
Abstract: Additive manufacturing promises high flexibility and customized product design. Powder bed fusion processes use a laser to melt a polymer powder at predefined locations and iterate the scheme to build 3D objects. The design of flowable powders is a critical parameter for a successful fabrication process that currently limits the choice of available materials. Here, a bottom‐up process is introduced to fabricate tailored polymer‐ and composite supraparticles for powder‐based additive manufacturing processes by controlled aggregation of colloidal primary particles. These supraparticles exhibit a near‐spherical shape and tailored composition, morphology, and surface roughness. These parameters can be precisely controlled by the mixing and size ratio of the primary particles. Polystyrene/silica composite particles are chosen as a model system to establish structure–property relations connecting shape, morphology, and surface roughness to the adhesion within the powder, which is accessed by tensile strength measurements. The adhesive properties are then connected to powder flowability and it is shown that the resulting powders allow the formation of dense powder films with uniform coverage. Finally, successful powder bed fusion is demonstrated by producing macroscopic single layer specimens with uniform distribution of nanoscale silica additives. Abstract : A bottom‐up process is presented for the production of micrometer‐sized polystyrene and polystyrene silica composite supraparticles from colloidal building blocks, with precise composition, morphology, and surface properties for powder‐based additive manufacturing. The controlled surface properties allow tailoring the powder flowability. It is demonstrated that composite materials with homogeneously distributed nanoscale additives can be produced by selective laser sintering.