Researchers from the École Polytechnique Fédérale de Lausanne (EPFL) have launched a compact, high-efficiency holographic tomographic volumetric additive manufacturing (HT-VAM) system that leverages a MEMS-based phase-only mild modulator. This improvement marks a major development in addressing the sunshine supply limitations related to volumetric 3D printing.Their work, detailed in a preprint on arXiv (June 2025) demonstrates how section modulation can revolutionize light-based fabrication, enabling sooner, higher-resolution prints with unprecedented vitality effectivity.
Holography meets volumetric manufacturing
Volumetric Additive Manufacturing (VAM) is a layerless 3D printing method that cures whole objects concurrently by projecting mild patterns right into a rotating vial of photoresin. In contrast to layer-by-layer strategies, VAM eliminates stair-stepping artifacts and permits support-free fabrication of complicated geometries. EPFL’s method, Tomographic VAM (TVAM), adapts computed tomography ideas to generate dynamic mild fields that polymerize resin volumetrically.
Conventional TVAM methods typically depend on Digital Micromirror Gadgets (DMDs), binary amplitude modulators with restricted mild effectivity, usually beneath 10%. The EPFL staff replaces these with a phase-only Section Mild Modulator (PLM), which permits exact wavefront management. This modification ends in a measured mild effectivity of 23.78%, representing a 70× enchancment over DMDs, whereas additionally decreasing imaging artifacts like speckle noise.
Section Modulation: A Recreation Changer
Till lately, Liquid Crystal on Silicon (LCOS) Spatial Mild Modulators (SLMs) have been the usual for section modulation. Nevertheless, LCOS suffers from limitations together with sluggish response occasions (60–120 Hz), ultraviolet (UV) degradation, and polarization sensitivity.
In distinction, EPFL’s MEMS-based PLM, developed by Texas Devices, makes use of piston-motion micromirrors to encode section immediately. It contains a 4-bit decision (16 section ranges) for exact wavefront shaping, excessive velocity (1,440 Hz body charge) for fast patterning and polarization insensitivity and UV stability, crucial for photopolymerization.
This structure permits using low-power, single-mode 405 nm lasers, decreasing each price and system complexity whereas attaining near-theoretical diffraction effectivity.
Speckle Discount and Print High quality
A key innovation lies within the system’s speckle-reduction pipeline. Speckle, brought on by interference in coherent mild, was mitigated via time-multiplexed projection of 9 laterally shifted holograms per angle. Mixed with Bessel beam axicon phases, this decreased speckle distinction by 50% (from 0.45 to 0.33) and prolonged the system’s depth of focus, guaranteeing uniform decision all through the print quantity.
Fast, high-fidelity printing
The system demonstrated fast printing of complicated fashions, equivalent to a 4 mm fusilli pasta construction in 32 seconds (18 mW laser energy), a Stanford Bunny (8 mm tall) in 61 seconds (50 mW) and DNA helices with clean surfaces at micrometer scales. Potential functions span bioprinting, micro-optics, and aerospace, the place velocity, decision, and materials effectivity are crucial.
Volumetric printing matures with improvements in mild management and biomedical functions
Volumetric additive manufacturing has gained momentum as a promising various to conventional layer-by-layer 3D printing, providing the flexibility to manufacture whole objects concurrently with fewer constraints on geometry and velocity. Current advances embody automated publicity management methods for extra exact mild dosing throughout tomographic projection, and using light-converting nanoparticles to allow deeper and extra managed polymerization. Swiss agency Readily3D, a spin-off from EPFL, has additionally superior volumetric bioprinting via its collaborations with BIO INX, aiming to simplify the fabrication of complicated organic fashions.
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Featured picture exhibits floor high quality enchancment comparability. Picture by way of Laboratory of Utilized Photonics Gadgets (LAPD), EPFL.
