Material Characterization and Strategies for Optimization of Additively Manufactured Electric Machines—A Review

With the advent of 3D printing, advancements in optimizing structures and innovations to 3D print new materials for electric machines are being developed. Conventional structures are being replaced by lattice structures which provide better properties. From plastics to metals, recent achievements have been made in the 3D printing of soft and hard magnetic materials. Hard magnetic materials are mostly printed by mixing them with ferrites or using a binder material. This paper focuses on all the different methods and compositions to 3D print metals and soft and hard magnetic materials. Although research is still undergoing to expand the use of different magnetic materials, we still have some limitations in their use in electric machines e.g., mixing hard magnetic materials with other materials for 3D printing weakens their electromagnetic properties. Some 3D printing processes provide a comparatively low mechanical strength. With research being undertaken to overcome these challenges, recent 3D-printed magnetic materials for the use in electric machines are discussed in this paper. Apart from materials, different optimization strategies are also introduced that increase the efficiency of the 3D-printed parts e.g., process optimization, topology optimization, and thermal optimization. Process optimization includes different multi-material strategies to reduce the time taken, print multiple parts in one process, and improve the properties of the part. Topology optimization revolves around optimized designs. The properties of electric machines are enhanced by using optimized shapes of rotor, stator, and coils. During the operation of electric machines, there is always some heat generation. The efficient removal of this heat from the system can increase the efficiency of the part. Thermal optimization to efficiently dissipate the heat to the atmosphere is achieved by using phase-changing materials (PCMs), by installing cooling systems, or by introducing optimized structures with better thermal properties. All these developments are discussed in this paper.