2024 AIChE Annual Meeting
(294c) Additive Manufacturing of Multi-Metal Structures with Adjustable Gradients Via Continuous Liquid Interface Production
Author
Metal additive manufacturing (AM), also known as metal 3D printing, has become the go-to technology for fabrication of high-quality metal and alloy components due to their high integrity and customizability providing a method for manufacturing intricate designs with broad applications within the biomedical, aerospace, and military sectors. Well-established AM technologies such as powder bed fusion, material extrusion, and binder jetting have demonstrated the ability to manufacture novel designs in comparison to conventional casting and injection molding techniques that are expensive and wasteful. However, these metal AM technologies have limited material selection and anisotropic properties that stem from the layer-based printing approach that is inherent to these methodologies leading to non-uniform grain size distribution and “staircasing” effect which can lead to undesired performance and have a negative impact on the exhibited physical properties of the metal structure. Furthermore, when fabricating metal objects with two or more metals, the powder recoating and particle fusion process is constrained by long print times and expensive hardware since each printable powder material has distinct melting characteristics and thermal properties that require precise process control to ensure part integrity. Recent developments of low viscosity printing resins with metal precursors utilizing continuous liquid interface production (CLIP) 3D printing have relaxed the challenges associated with poor surface roughness and printing speed of meso- and microscale functional metal devices allowing for next-generation thermal management devices and metamaterials with isotropic performance. Moreover, the continuous AM technologies can be utilized to enable the fabrication of multi-metal components with composable gradients with tunable physical properties and print times that are orders of magnitude faster compared with traditional metal 3D printing. Consequently, the research presented here aims to address key performance parameters, including material deposition, printing performance of metal salt resins, thermal characteristics of multi-metal precursors, and post-processing settings, in order to develop a novel AM technology that can achieve multi-metal objects with homogeneous grain size distribution and tunable physical properties at higher resolutions. Single and alloy metal salt printing resin with low viscosity are synthesized utilizing inorganic metal salts enabling the fabrication material to be evacuated and refilled in a facile manner during the 3D printing process to achieve metal components with more than one metal. Experimental data on the post-processing parameters of multi-metal precursors indicate that both dense and porous multi-metal structures can be achieved via the mask-video projection vat photopolymerization with resin exchange process. Additionally, gradient metal components exhibit excellent surface quality, smooth material transition regions, and homogenous microstructure with uniform grain sizes on the top, bottom, and front faces. Lastly, the broad impact of this work is discussed, and a comparison is made between the microstructures and surface quality of multi-metal printed structures using the proposed approach with current state of the art metal AM technologies.
