Optimization of the UV-curing and magnetic capabilities of a magnetite 3D printable resin for metamaterial applications

The manufacture of acoustic metamaterials (AMMs) is a significant challenge within the field, which developments in additive manufacture have the potential to address. This research presents the optimization of a new Stereolithography (SL) 3D printable resin, with magnetic properties incorporated to be utilized in adjustable AMMs. The core aim of this study is the synthesis of a magnetic resin for improved adjustable-bandwidth performance in membranecoupled AMMs. The material features considered relevant here for resin optimization are curing rate, Young’s modulus, and magnetization of saturation. Studies were conducted to analyze the effect of various resin components, comprising single and interpenetrated polymer networks, surfactants, photoblocker concentrations, and magnetic fillers, on the resin properties. Magnetic hysteresis plots were recorded to demonstrate the effect of using different particle sizes of magnetite and carbonyl iron. The goal of this is to optimize the magnetic composite selection to maximize magnetization while reducing the need for magnetic poling post-manufacture, further contributing to the ease of manufacture of the resin formula. The final formula had a density of 1205.30±0.56 kg/m³, peak tensile Young’s modulus of 6.50 MPa and ultimate tensile strength of 0.744 MPa - printed with 25 𝜇m layer thickness. The magnetization of saturation for the optimized resin formula was 3.326 - 4.647 emu/g at 5 %wt magnetite content, dependent on the poling regime.