A vat photopolymerization process for structures reinforced with spatially steered flexible fibers

Khatua, V and Gurumoorthy, B and Ananthasuresh, GK (2024) A vat photopolymerization process for structures reinforced with spatially steered flexible fibers. In: Additive Manufacturing, 86 .

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Abstract

We present a modified vat photopolymerization process for realizing novel fiber-reinforced composite parts wherein continuous fibers are selectively positioned and oriented across multiple layers along the build direction. This is in contrast to laminates and fiber-wound parts made by repeating fiber patterns; and additively manufactured parts with fibers inserted a posteriori or co-extruded selectively. Our process endows two benefits to the parts made with it: (i) spatially steered fibers embedded along specific paths inside to increase stiffness and strength; and (ii) in-situ fiber-matrix interface concurrently cured with matrix material as opposed to the matrix-matrix interface that exists in co-extruded fibers. The process is enabled by a robot manipulator that guides the fiber in each layer by incrementally orienting it along the tangential direction to the bespoke path. The robot arm and the end-effector do not obstruct the UV light source as they pull the fiber taut from afar in multiple directions to alleviate the undesirable effects of shadows. The robot arm is integrated with the build platform and the UV projector, and the entire process is automated. Examples that illustrate making parts with single and multiple fibers are presented to show the efficacy of the process and the machine. An example is shown with continuous fibers embedded along a few spatially varying principal-stress-flow paths inside a part to improve its stiffness and strength. An increase of 71 in stiffness and 90 in strength of the part is observed at fiber volume fraction as small as 0.39 . © 2024 Elsevier B.V.

Item Type:	Journal Article
Publication:	Additive Manufacturing
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to Elsevier B.V.
Keywords:	3D printing; Additives; End effectors; Fiber reinforced plastics; Light sources; Manipulators; Photopolymerization; Robotic arms; Stiffness; Stiffness matrix, Additive manufacturing of composite; Continuous fibers; Embedded fiber composite; Embedded fibers; Fibre composites; Optimisations; Optimization of fiber composite; Photo polymerization; Robot arms, Fibers
Department/Centre:	Division of Mechanical Sciences > Department of Design & Manufacturing (formerly Centre for Product Design & Manufacturing) Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	03 Jun 2024 10:26
Last Modified:	03 Jun 2024 10:26
URI:	https://eprints.iisc.ac.in/id/eprint/85114

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