Overprinting with Tomographic Volumetric Additive Manufacturing

Abstract: Tomographic Volumetric Additive Manufacturing (TVAM) is a light-based 3D printing technique capable of producing centimeter-scale objects within seconds. A key challenge lies in the calculation of projection patterns under non-standard conditions, such as the presence of occlusions and materials with diverse optical properties, including varying refractive indices or scattering surfaces. This work focuses on demonstrating a wide variety of overprinting scenarios. First, utilizing a telecentric laser-based TVAM (LaserTVAM), we demonstrate the printing of a microfluidic perfusion system with biocompatible resins on existing nozzles for potential biomedical applications. In a subsequent demonstration, embedded spheres within the bio-resins are localized inside this perfusion system, optimized into specific patterns, and successfully connected to the nozzles via printed channels in less than three minutes. As a final LaserTVAM example, we print gears on a glossy metal rod, taking into account the scattered rays from the rod's surface. Using a non-telecentric LED-based TVAM (LEDTVAM), we then overprint engravings onto an existing LED placed in the resin. With an additional printed lens on this LED, we can project those engravings onto a screen. In a similar application with the same setup, we print microlenses on a glass tube filled with water, allowing us to image samples embedded within the glass tubes. Based on a differentiable physically-based ray optical approach, we are able to optimize all these scenarios within our existing open-source framework called Dr.TVAM. This framework enables the optimization of high-quality projections for both LaserTVAM and LEDTVAM setups within minutes, as well as lower-quality projections within seconds, outperforming existing solutions in terms of speed, flexibility, and quality.