Continuous Volumetric 3D Printing: Xolography in Flow

Abstract

Additive manufacturing techniques continue to improve in resolution, geometrical freedom, and production rates, expanding their application range in research and industry. Most established techniques, however, are based on layer‐by‐layer polymerization processes, leading to an inherent trade‐off between resolution and printing speed. Volumetric 3D printing enables the polymerization of freely defined volumes allowing the fabrication of complex geometries at drastically increased production rates and high resolutions, marking the next chapter in light‐based additive manufacturing. This work advances the volumetric 3D printing technique xolography to a continuous process. Dual‐color photopolymerization is performed in a continuously flowing resin, inside a tailored flow cell. Supported by simulations, the flow profile in the printing area is flattened, and resin velocities at the flow cell walls are increased to minimize unwanted polymerization via laser sheet‐induced curing. Various objects are printed continuously and true to shape with smooth surfaces. Parallel object printing paves the way for up‐scaling the continuous production, currently reaching production rates up to 1.75 mm for the presented flow cell. Xolography in flow provides a new opportunity for scaling up volumetric 3D printing with the potential to resolve the trade‐off between high production rates and high resolution in light‐based additive manufacturing.This article is protected by copyright. All rights reserved

Light from Afield: Fast, High-Resolution, and Layer-Free Deep Vat 3D Printing

“…While impressive in its achievable resolution, this initial demonstration of xolography did not feature cytocompatible applications. Further work advanced the initial setup into a continuous process, where dual-color photo-cross-linking was performed inside a flow cell (FlowXube) with continuously flowing resin (Figure B) . The technique enabled an upscaling in the production rate while maintaining high resolution of the printed parts.…”

“…B. Application of xolography in flow to enable continuous high-throughput printing: 3D model of the print (i), in situ observations of the print in the flow cell (ii), and SEM image showing high printing fidelity and smooth surfaces (iii) (reproduced from ref copyright 2023 Wiley under CC-BY 4.0). C. Light-sheet 3D printing setup consisting of two laser beam paths .…”

“…To create physiological-sized hydrogel constructs with aligned filaments, this approach can leverage the precise control of light penetration depth and photoresin flow, ensuring that while the macro-level constructs are adequately photo-cross-linked, the internal microstructure still has the microscale configuration induced by the self-focusing effect. Similarly, these principles are applicable to light sheet-based stereolithography; when combined with the continuous feed of resin, the creation of extensive and coherent structures is possible …”

“…A common understanding is that a volumetric printing approach should generate the entire volume of the 3D printed structure simultaneously through light projection, which would encompass the techniques of multidirection projection , or tomographic printing. , However, there are other techniques which feature some commonalities in terms of the process principles of light propagation deep into the volume of resin vat, as well as the photoinitiation and cross-linking mechanisms. These include light sheet-based stereolithography , or filamented light (FLight) biofabrication. , Given the fact that the cross-linking is taking place in a volume of resin-filled vat, the term volumetric printing has also been used for light sheet-based techniques such as Xolography. , To circumvent these discrepancies, we instead propose the use of the term “Deep Vat” printing in this review, to be able to cover all four techniques together. This also allows one to distinguish between Deep Vat printing (DVP) methods and the more conventional techniques, where only a small region of the material within the vat is available for photo-cross-linking at a time.…”

4D printing for biomedical applications

“…VAM, a layerless method, achieves individual voxel crosslinking by irradiating dynamically evolving light patterns onto a rotating resin vial, facilitating the creation of 3D structures. In recent years, a slew of scientific breakthroughs exemplified by technologies such as CLIP (Continuous Interface Liquid Production) 17 and iCLIP (injection Continuous Interface Liquid Production), 18 HARP (High-Area Rapid Printing) 19 has transformed 3D printing beyond its traditional role in small-scale prototyping, propelling it into the realm of commercial manufacturing, 20 whereas technologies such as CAL (computed axial lithography), 21,22 xolography 3D printing, 23,24 MM3D (Multimaterial Multinozzle) printing, 25 RM-3DP (Rotational Multimaterial 3D Printing) 26 have introduced unprecedented capabilities and expanded the horizons of 3D printing.…”