On anisotropy, strain rate and size effects in vat photopolymerization based specimens

The influence of build orientation, layer thickness, strain rate and size effect on the Young's modulus, ultimate tensile strength and fracture strains in vat photopolymerization based additively manufactured specimens is investigated. Mechanical testing and subsequent scanning electron microscopy tests on additively manufactured specimens are conducted. Anisotropy in mechanical behavior is only observed in specimens fabricated in different planes. An increase in layer thickness and decrease in strain rate resulted in lower strength, stiffness and higher fracture strains. No significant size effect on strength and failure strains is observed. Cure kinetics is found to have significant influence on mechanical properties of additively manufactured specimens.