Motor concept for smaller and more efficient 3D production lines

For the development of a quasilinear transport system with 3D tracks, Technische Universitaet Braunschweig (TU-BS) decided to include stator elements based on Somaloy technology. The research has resulted in a much more efficient solution for production line transport.

Conventional production lines use transport systems that are rather slow and have large footprints. These disadvantages tend to increase when curvatures and differences in levels are required. In order to develop a more efficient solution for such 3D production lines, a project with a twisted linear motor was initiated by the Institute for Electrical Machines, Traction and Drives (IMAB) about 10 years ago.

The modules contained identical stator teeth which were placed in the direction of the mover. Using Somaloy, the SMC material from Höganäs, made it possible to press each stator tooth into one single component with the specially developed geometrical shapes required for the 3D curvature set-up. In turn, this allowed a displacement of each tooth in all directions to create a long 3D curved stator that followed the track. Since the motor concept required a large number of stator teeth as well as an integrated functionality in each tooth’s shape, pressing technology was perceived as having a big advantage over laminated steel.

The vehicle used for the transportation system was equipped with permanent magnets on both sides. Applying this technology enabled the creation of a passive mover requiring neither signal nor power cable. The increase in velocity required by the system’s acceleration section was achieved by installing stator modules on both sides of the track and by also increasing the number of windings in that particular section.

Höganäs assisted TU-BS in the use of Somaloy for optimal component performance and also suggested a suitable pressing company. Canders says that the project has involved a learning process between TU-BS, Höganäs and the pressing company, referring to the heat-treatment procedure as one example. “While the pressing company has normally conducted the heat treatment of its components in a nitrogen atmosphere, Höganäs advised an air atmosphere to avoid corrosion and improve strength.”

According to Canders, Somaloy plays an important role in the impressive performance of the application. He mentions, particularly, two of the material’s major features: the suppression of eddy currents and, the most important feature for this project, freedom of design. “Using Somaloy enabled us to make use of the design flexibility to design electrical machine parts with optimal shapes and to arrange 3D flux paths that lowered the losses. In addition, Somaloy also enabled us to design more compact parts, thereby saving space.”

While the quasilinear drive system has successfully gone through a number of tests, IMAB is still working on optimising procedures and further reducing mass and volume. Knowledge about this technology and SMC materials has increased considerably during the project, and the group of researchers at IMAB is already thinking about how the findings can be applied to other suitable applications. “We have continued to work with SMC materials ever since first discovering their possibilities. Whenever we are dealing with problems with possible 3D solutions, Somaloy will be considered, as it can play an important part,” says Canders.

According to Canders, there are many possible applications that could benefit from the developed motor concept, ranging from packing and wrapping machines to linear tooling stations and printing machines with very complex transportation routes.

Höganäs AB
www.hoganas.com