Ultrasonic measurements of the orientation dependence of the mechanical properties of 3D printed objects*

As additive manufacturing becomes increasingly prevalent, it is critical to understand the mechanical properties of the resulting 3D printed objects. These objects are often used as parts in larger structures and can be critical support elements in complex devices. The broad range of customization options provided by the 3D printing process can drastically affect the physical properties of the resulting parts. In this study, we examine the orientation dependence in the mechanical properties of filament-based 3D printed objects using ultrasonic methods. Using a through transmission technique, the speeds of sound in printed objects were measured in three orientations to determine the anisotropy in the stiffness parameters. Objects constructed of three common filament types were examined. We found significant variations in the compressional modulus among the orientations with differences as high as 40% in some cases. These findings indicate that the anisotropy in mechanical moduli should be a critical consideration in the additive manufacturing process.