Researchers at Lund University (Sweden) have developed a technique for making magnetic components in electric motors from plastic bonded iron powder (PBIP) that can cut aggregate production cost in half and nearly double the output of the motor. The method is the result of 15 years of collaboration between researchers from the fields of electrical power systems and industrial production.
A key component in motors is the magnetically conductive material, usually made up of bundled laminated thin plates with coils wound around them. This type of motor construction contains many small parts and takes a long time to manufacture.
Together with his research colleagues Tord Cedell and Mats Andersson, Lund Professor Mats Alaküla has found that an alloy of iron powder in plastic (PBIP) functions well in such motor applications. The concept of PBIP is to surround the metal particles with insulating plastic material to provide low conductivity and high permeability. Properties of PBIP vary depending upon the shape of the metal particles and the choice of plastic material.
Centrifugal molding is used to arrange and pack the metal particles in an optimized structure—i.e., with better arrangement than if molded without centrifugation, but not too dense to allow contact between particles.
Molding melted plastic and iron particles also enables full freedom of form. Besides higher quality and greater freedom of form, the technique reduces the number of production steps from about 60 to only a few. The development of the material itself started in the late 1980s at the Section for Industrial Production, within the framework of the materials technology consortia, funded partly by what is now Vinnova (Research and Innovation for Sustainable Growth).
This research is funded with a total of SEK 12 million (US$1.9 million) over five years from Vinnova, the Foundation for Strategic Research (SSF), and Industri Kapital. A patent is pending, to be issued in late October. Whether a new company will be formed or the technology licensed out has not yet been decided by the researchers at CEMEC (Center for Electro-Magnetic Energy Conversion).
The technique is not suitable for high-performance motors, such as servo motors. But for fans, pumps, household appliances, and cars it’s a perfect fit. The technology can pave the way for new possibilities, such as facilitating the conversion of cars to electric hybrid power. It’s worth mentioning in this connection that all methods that lead to simpler and cheaper production indirectly help curb carbon dioxide emissions.—Mats Alaküla
A prototype of the technology will be on display at the Lund University Faculty of Engineering booth at the Technology Fair in Älvsjö, Stockholm, Sweden, 16-19 October.