Selective dissolution of polysulfone support material of fused filament fabricated Ultem 9085 parts

One of the main advantages of 3D printing lies in the fact that the desired object is constructed layer by layer, enabling the production of complex geometries otherwise unfeasible with conventional manufacturing methods. To create these parts, the use of an auxiliary scaffold structure, made of either the same or a different material than the model, is usually mandatory to avoid structural collapse during fabrication. Such support materials need to be chemically or manually removed after the part is manufactured. However, the removal process can potentially damage the object and poses a problem when the part presents intricate or hidden cavities. This study presents a time-effective, temperature-controlled methodology to dissolve the only commercially available Ultem™ 9085 (Ultem) support material. The process to select a novel solvent and its effects on Ultem's mechanical performance in terms of compression, tensile and bending properties is addressed. At the same time, the influence of the chemical post-process on Ultem's flammability is evaluated, given that the FST (flame, smoke, and toxicity) certification of this material is one of the most attractive properties for its applicability in certain industrial sectors. Results are supported by optical and scanning electron microscopy. The outcomes of this research are intended to provide practical recommendations for the use and scaling of the proposed solvent by the industrial sector.