Multimaterial Vat Polymerization Additive Manufacturing

Abstract

Additive manufacturing is the process of creating an object from a digital three-dimensional (3D) design using hardware that deposits and adds materials successively until the desired object is formed. Vat polymerization is a type of additive manufacturing technique that offers an attractive strategy for fabricating 3D objects due to its high resolution, versatility of feedstock materials, and high dimensional accuracy. However, the ability to spatially control the placement of multiple materials during vat polymerization is limited by mechanical designs that can restrict printing to a single photocurable resin, making it difficult to create complex geometries with embedded functionality. In this review, we highlight work-arounds that have been employed, such as manually switching resins, as well as two key areas of innovation: mechanical hardware design and the chemistry of materials. These methods include systems which automatically switch resin vats, volumetric additive manufacturing which overprints a secondary 3D structure on top of an existing object, and specially formulated, unique material chemistries, such as those which enable dual wavelength light to initiate orthogonal chemistry mechanisms, control of the degree of cross-linking with variation in light parameters, and phase separation of functional materials. Perspectives on the interplay of printer type and material chemistry, the constraints they impose on one another, and the future of multimaterial vat polymerization are described. In order for vat polymerization to emerge as a viable technology for multimaterial additive manufacturing, both mechanical hardware design and chemistry of materials must be codeveloped.

Wavelength Orthogonal Photodynamic Networks

“…While photoinitiated chain growth polymerizations have seemingly exhausted their capability for wavelength-orthogonal curing, the individual curing of each network remains, to the best of our knowledge, unexplored. [55] Furthermore, the formed bonds are not dynamic post-printing. Utilization of light-stimulated reversible ligation reactions could instead lead the way towards dynamic material behavior postprinting.…”

“…However, these processes enabled curing of both, the cationic and radical resin, under UV irradiation, resulting in IPNs, or radical‐only curing upon irradiation in the vis range. While photoinitiated chain growth polymerizations have seemingly exhausted their capability for wavelength‐orthogonal curing, the individual curing of each network remains, to the best of our knowledge, unexplored [55] . Furthermore, the formed bonds are not dynamic post‐printing.…”

A Review on Additive Manufacturing of Micromixing Devices

“…Additionally, if it is necessary to improve the properties of these resins, additives can be incorporated into the photopolymer resin [209] . In addition, to obtain more advanced material properties, an interesting application of vat is multimaterial vat polymerization, which can provide materials with higher impact absorption and resistance to fracture [210]. An example is [211], where methacrylate-based commercial resins with carbon fibre additives are used, obtaining microlattices of high stiffness but also energy dissipative as elastomers.…”

A Review of Multi-Material 3D Printing of Functional Materials via Vat Photopolymerization

“…Additive manufacturing, often termed 3D printing, is a comprehensive materials development technique which has gained signification attention following its discovery in the 1980s [1][2][3][4][5][6][35][36][37]. At present this technology is experiencing significant growth and can now be applied using a wide range of methods, including material jetting [38,39], binder jetting [40,41], material extrusion [42][43][44][45][46], powder bed fusion [47,48], vat photopolymerization [37,[49][50][51][52][53], and sheet lamination [35,36,54,55].…”