Additive Manufacturing Processes for Structural and Hybrid Architectured Materials

Architectured materials have gained significant attention in recent years due to their unique properties and potential applications, such as lightweight structural materials and functional devices. Projection stereolithography is a promising additive manufacturing technique for fabricating these materials with precisely designed geometries. However, several key processing factors have limited the development of this technique. One of the primary challenges of using projection stereolithography is the limited control over printing material properties, especially resin viscosity. High-viscosity resins may not flow easily or could potentially result in the loss of fine details in the final print. Another challenge is structure printability, as the geometrical arrangement of building blocks to create the desired microstructure may lead to overhanging features or unsupported regions. Such design complexities can result in deformation, detachment, or even collapse of the printed structure. Size scalability is another challenge in projection stereolithography, which is inherently restricted by the pixels of the light engine.This work focuses on addressing the aforementioned challenges by developing new additive manufacturing processes. Specifically, an extendable multi-material projection stereolithography system integrated with a tape-casting method is developed to create architectured lattice materials made of carbon fiber reinforced polymer composites. This system improves material processability by allowing for precise control of resin fluidity. Then, a light-based approach capable of printing arbitrary micro-architectures with a large array of internally suspended features is presented. This method eliminates the need for manual removal of internal supports, which improves structure printability. It also enables the creation of multi-functional metamaterials with a range of designed properties, including wide bandgaps for elastic waves and switchable wave transmissions. Lastly, a large-scale high-resolution scanning projection stereolithography process integrated with an optical scanning system is presented. This system provides the ability to print unprecedented large-scale parts of 50 cm with a minimal feature size of 50 μm, which enables the fabrication of architectured materials with features spanning over four orders of magnitude for many applications. Overall, these proposed approaches address several critical challenges in the projection stereolithography process and have a profound impact not only on the industry but also on other research works