Belgian consortium tries to make better electric motors using 3D printing –

A Belgian consortium consisting of the University of Ghent, KU Leuven and the research organization VITO worked on the Additive Manufacturing for Electrical Machines (AM4EM) project. They want to make more energy-efficient electric motors. Startup Additive Drives along with several companies in the automotive supply chain are taking a close look at electric motors, windings and 3D printing engine components. It can have a much wider impact than cars, but many engines find their way into bicycles, industrial equipment, and many other things that populate our daily lives.

The group specifically studies 3D printing stators and rotor cores. In electric motors, the stator usually contains magnets while the rotor contains windings that carry current. There is an air gap between the two while a bearing allows the rotor to spin smoothly inside the stator. The windings are wound in different directions and current flows through them. Magnets exert forces on these windings in different directions, creating a torque that spins the rotor as current is applied. There are millions of DC and AC motors around the world and they can be very small or room-sized. In general, people have optimized the parts and geometries and designs of these things pretty well over the past 100 years.

What the trio of Belgian research groups are trying to do is apply multi-material 3D printing to engines. With multi-material 3D printing, we can lay down different materials, mix them together, and create different configurations of those materials or layers with different materials. They hope that by doing this they can find methods to make more efficient motors that optimize the magnetic fields or forces involved in ways that have not been possible until now.

A VITO copper print

Vito has been researching 3D printing since 2006 and has a particular interest in printing pastes using ceramics, metals and polymers. A sign of progress is that the team printed pure copper paste, demonstrating that “micro-extrusion 3D printing of copper paste led to printed parts with no printing defects, a relative density of 95 at 99% and an impressive electrical conductivity of 90 – 102% IACS [International Annealed Copper Standard].”

An Fe-Si print by VITO

The team also printed an Fe-Si (also known as electrical steel, often used as a base motor material). The team is now working on printing parts for the core where the ceramic is printed in one layer followed by an Fe-Si layer. At the moment they have significant distortions and shrinkages, but they hope to be able to optimize the cores.

A metal filament copper print bound by KU Leuven

While VITO has focused on paste extrusion, KU Leuven is working on FDM for metal and ceramics similar to the bonded metal process used by Desktop Metal, Nanoe and Markforged. Here they also tried to mix the materials in one print. Ghent University is in turn working on optimizing motor design to improve magnetic flux. The trio hope to increase the energy efficiency of their motors by 5% and have a power density increase of 40% by the end of their project.

I really like this approach. Given the volume and importance of electric motors, a small improvement can potentially have a big impact. Now, of course, if we only have a marginal impact, it will be difficult, if not impossible, to get battery manufacturers to adopt our technology. If the impact is large enough, we will still have an advantage that could cover the problems and costs of adopting new production technology. What is also potentially very fruitful is that the filament process and the paste process used here are inexpensive. These could be very cost-effective technologies to implement on a very large scale. They are capricious at the moment but are promising. They would need a lot of automation, especially since they require a separate debunking and sintering step. But, if that is overcome, they could very well make some pretty profitable coins.

Images courtesy of VITO, KU Leuven and Ghent University.