Virtual Volumetric Additive Manufacturing (VirtualVAM)

Abstract

Tomographic volumetric additive manufacturing (VAM) produces arbitrary 3D geometries by exposure of a rotating volume of photopolymer resin to tomographically-patterned illumination. This enables high speed, layer-less printing of parts from a wide range of photopolymers not amenable to layer-by-layer processes. Since the entire geometry is produced at once over the course of a few seconds to minutes, molecular diffusion length scales become significant to the printing process. Understanding these molecular reaction and diffusion processes is imperative for advancing VAM to a usable technology. These processes are experimentally very difficult to monitor and measure. Herein, VirtualVAM - a simulation framework for modeling the tomographic VAM process, is developed and experimentally validated. VirtualVAM simulates reaction, diffusion, and heat generation processes over the course of a print with single-voxel resolution. From a few experimentally-determined input parameters and a set of images for projection, VirtualVAM is able to generate a large spatio-temporal data set for any given tomographic VAM print. Using VirtualVAM, a number of experimentally-unattainable aspects of the VAM process are investigated such as single-voxel conversion profiles, effect of molecular oxygen, and stopping time determination. VirtualVAM also enables the optimization of exposure patterns to further improve contrast between in-part and out-of-part delivered dose.