Additive Manufacturing for Electrical Machines (AM4EM) is an ongoing Belgian research project by VITO, KU Leuven and Ghent University, on the use of Additive Manufacturing to create more energy-efficient electrical motors (stator/rotor cores). The main challenge in creating the perfect motor is combining conductive and insulating materials into complex multi-material geometries. As multi-material Additive Manufacturing is still in its infancy, however, all technologies and designs must be thoroughly
VITO is an independent research organisation working in the area of green technology and sustainable development. The organisation has been working with Additive Manufacturing since 2006 with a focus on additively manufacturing viscous powder-loaded paste. This paste-based Additive Manufacturing is one of the technologies used in the AM4EM project.
Some important steps forward are said to have been realised. Micro-extrusion Additive Manufacturing of copper paste has led to parts without build defects, a relative density of 95-99% and an electrical conductivity of 90-102% IACS.
Positive results have also been reported with the Additive Manufacturing of Fe-Si steel, needed for the cores of the motors. The next step is to additively manufacture multi-material combinations for the magnetic core stacks, whereby a layer of ceramic insulator alternates with Fe-Si steel layers.
Although the results look satisfying at first sight, there are still challenges related to, for example, uniform shrinkage of the material and warping of the layers.
KU Leuven is known in the Additive Manufacturing industry for having been at the birth of Materialise and Layerwise (now 3D Systems). In this project, the organisation is focusing on Fused Filament Fabrication (FFF) technology for metals and ceramics. More specifically, it is additively manufacturing polymer filaments with a high content of metal or ceramic powder. The polymer in the filament is only needed to make the material additively manufacturable and is removed afterwards. Here, too, the challenge is only partially related to the Additive Manufacturing process itself; debinding and sintering require careful analysis as well to determine the optimal parameters such as temperatures, solvents, extrusion width or speeds, etc.
KU Leuven’s efforts, too, are said to have resulted in relative density results above 95% for copper and 97.3% for ceramic, including in combinations of both materials in one build.
Ghent University has experience in multi-physics models for electrical machines and was a part of the project to better understand how the design of crucial motor parts impacts how the electrical currents interact with the magnetic field to create torque. As a consequence, the design details strongly determine how efficient your machine will ultimately be.
These combined efforts on different Additive Manufacturing techniques, design and material improvements, are hoped to deliver innovative MM-AM processes applicable to sensors, radars, actuators, electrical machines, etc. Ultimately, AM4EM targets an increase in energy efficiency by 5% point (compared to small induction machines) and an increase in power density by 40%.