Volumetric additive manufacturing (VAM) is a newly developed polymer 3D printing technique that uses tomographic light patterns to fabricate complex 3D objects all-at-once. This volumetric printing platform, however, introduces challenges with photoresin requirements. In this presentation, we will discuss the constraints imposed by VAM on the photoresins and the strategies we are using to circumvent these constraints. The advances, made by understanding the dynamics of acrylate-based chain growth polymerization in 3D volumes, have led to photoresins capable of printing larger objects four times faster with higher resolution. These breakthroughs in photoresin formulations significantly broadens the application space for VAM as it can generate intricate polymer objects with exceptional print fidelity with surface finishes of optical quality.
Volumetric additive manufacturing (VAM) via tomographic projection is an emerging platform for ultra-rapid 3D printing. By projecting all layers in parallel, print times orders of magnitude faster than standard polymer 3D printing can be easily achieved, without the need for support scaffolds. Despite these advantages, print results are in certain cases inferior to commercial vat polymerization due to the infancy of the technique. In this talk, we will outline recent progress made at the National Research Council of Canada to extend the capabilities of VAM and address inherent challenges in VAM. Topics covered will include the role of depletion and polymerization kinetics on print quality and novel resins for larger, faster, and functional prints.
In this talk, we present a new methodology for computing projections in tomographic additive manufacturing. Currently, tomographic printing systems require that light-rays in the printing volume are parallel, and have low etendue. In this work, we show that accurate modeling of the light rays through the print volume enables improved printing in systems with diverging beams. We also demonstrate that ray-tracing can compensate for non-parallel projection in 3D. We anticipate that our ray-tracing methodology will relax the hardware requirements necessary in the conventional Radon-based approach, and enable a broader range of tomographic printing configurations.
In this talk, we will present our observations of printing kinetics in light-based tomographic additive manufacturing using optical scattering tomography. In particular we report a feature-size dependence on polymerization time that contributes significantly to errors in the printed object: small features tend to polymerize more slowly than large features. Therefore, prints are either missing small features or large features are overexposed. We investigate the cause of this feature size polymerization time dependence and present techniques to correct for these errors.
Tomographic printing is a 3D printing technique that enables fast, supportless fabrication wherein light is projected through a rotating vial containing a photocurable resin. Usually, vial is placed in an index-matching bath to eliminate refraction at the vial surface. In this talk we will describe our approach to build an easy-to-use tomographic printing system that eliminates the index-matching bath. We use a computational ray-tracing approach to pre-distort projection images to exactly counteract the distortion from refraction at the air/vial interface and projector non-telecentricity. We will show simulation and print examples and expand on recent improvements in our system.
Light-based 3D printing techniques use patterned light, triggering polymerizations within a volume of a photoresin and yielding 3D objects. The process of printing in a vat of resin using light that varies temporally and spatially creates dynamics within the resin that ultimately influences properties of the printed part. This presentation will cover how concentration gradients and changes in miscibilities during printing causes phase separation and diffusion of species that effect the printing process. By tuning the formulations, changes in diffusitivity, viscosity and gelation rates can be control and therefore allow control over phase separation or deviations from nominal print dimensions.
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