An assessment of thermosetting infiltrate in powder-based composites made by additive manufacturing

Rapid prototyping for material deposition or additive manufacturing has been widely used for short time production of parts with complex geometry in small series. The three-dimensional printing process needs post-processing to improve the strength, stiffness and/or surface finish of the parts. Printed parts in pristine condition are generally very brittle with a porous structure, so infiltrates have been introduced to improve their mechanical and physical characteristics. This work investigates the effect of two infiltrates, epoxy polymer and cyanoacrylate, under a vacuum pressure system on the mechanical properties of powder-based composites made by three-dimensional printing. Samples printed under pristine and infiltrated conditions were tested under tensile, flexural, compressive and impact loadings. The infiltrated samples achieved superior mechanical properties, especially when the epoxy polymer was applied via a vacuum system. The microstructural analysis showed that the infiltrates were not able to penetrate the entire sample, revealing a porous structure in the centre, mainly when the cyanoacrylate was used. The epoxy polymer infiltrate was able to substantially increase the mechanical performance of three-dimensional samples, being a promising material when higher structural requirements are required.