Canadian researchers develop cold spray AM method for magnets
The method uses material in fine powder form accelerated in a high-velocity compressed gas jet. A stream of powder is sprayed at high speeds, hitting a specific target and building up layer by layer.
Researchers at the National Research Council of Canada (NRC) have developed an innovative manufacturing method to make magnetic materials.
Fabrice Bernier and Jean-Michel Lamarre have developed a new process for the fabrication of high-performance magnets for electric motors. These magnets are traditionally made by a process called powder compaction (for sintered magnets) or injection moulding (for bonded magnets) and must first be fabricated and then shaped and assembled into a final product.
The researchers at NRC have developed a cold spray technology that brings all steps together, reducing the time and cost to make the magnets but also expanding design possibilities.
“This technology will allow the creation of more compact, better performing motors for the future and could pave the way for building entire motors using cold spray technology, offering significant advantages such as cost reduction, better thermal management and more complex geometries and functionalities,” explains Fabrice Bernier.
This new additive manufacturing method uses material in fine powder form, which is then accelerated in a high-velocity compressed gas jet. A stream of powder is sprayed at high speeds, hitting a specific target and building up layer by layer.
The team was able to control the process and create complex shapes by including industrial robots, that perform rapid and precise 3D movements. The cold spray technique has the advantage of very high buildup rates that allow the production of several kilograms of magnets per hour.
The magnets produces using this new method have excellent mechanical and thermal properties. The high velocities used in the deposition of the material and the absence of polymer in the material matrix combine to give the magnet intrinsic mechanical properties that are far superior to conventional magnets. The adhesion of the magnetic material to the surface of the part is exceptional, since neither glue nor assembly is used.
Another advantage of this method is it enables the magnets to be easily machined. The NRC technology also offers magnets with increased thermal conductivity which allows for better temperature control. These magnets are corrosion and oxidation resistant and will therefore have a longer lifespan.
The NRC researchers have tested this new technology and are looking for new ways to use cold spray additive manufacturing to enhance motor design. With a push to reduce CO2 emission, the team has been focusing on developing next-gen electric motors. However, this method can help many different applications including magnetic cooling, wind turbines and telecommunication devices.