Mechanical properties of bending 3DP models of different thickness infiltrated with alternative materials
Edwin Ocaña-Garzón, Jorge Lino Alves
Binder jetting is a well-established three-dimensional printing (3DP) process to produce models with different purposes. These prototypes need to be infiltrated to increase the mechanical resistance, but depending on the type of infiltrant and models thickness, the penetration depth varies, and consequently their strength. In this research, three types of epoxy resins with dissimilar viscosities were selected to determine their influence on the flexural properties of the models, and evaluate the correlation between thickness and type of infiltrant. The molecular structure, viscosity and flexural strength of the resins were firstly characterized, and then 3DP bending samples with 2.5, 3.2 and 9.0 mm thickness were infiltrated by full immersion, and cured to the same conditions as the pre-tested resin samples. The infiltrated 3DP samples were characterized in terms of their porosity reduction and flexural properties. The results obtained allow to conclude that the thickness of the samples has the most significant effect on the flexural strength, while for flexural modulus, the contribution of resin type is more important. For better results, the amount of resin retained in the parts should be maximized, noting that, for thicknesses greater than 3.2 mm low viscosity resins perform better, while for thinner thicknesses, resins of moderate viscosity seem to be more adequate. It was concluded that infiltrates with short pot life could be better to avoid post-drainage of the infiltrant.