Dipl.-Phys. Thomas Schliesch will Deliver A Speech on 2019 Small Motor Industry Technology and Development Forum --The 17th Shenzhen (China) International Small Motor, Electric Machinery & Magnetic Materials Exhibition
Time: May 8-10, 2019 Venue: Shenzhen
It is our honor to invite Dipl.-Phys. Thomas Schliesch to deliver a speech with the topic of “Injection Molded Magnets for Electrical Machines”on 2019 Small Motor Industry Technology and Development Forum, which will be held concurrently during The 17th Shenzhen (China) International Small Motor, Electric Machinery & Magnetic Materials Exhibition (Motor & Magnetic Expo for short) at Shenzhen Convention & Exhibition Center on May 8-10, 2019.
Brief Introduction of Dipl.-Phys. Thomas Schliesch
Dipl.-Phys. Thomas Schliesch, Head of Research & Development, Max Baermann GmbH
Thomas Schliesch graduated in Physics from university of Hamburg in 1988 and joined the Max Baermann GmbH, which is a well known manufacturer of bonded magnets in Germany, in 1989. Since 1993 he is head of research & development at Max Baermann GmbH. Thomas has filed various patents for permanent magnetic systems. A major part of his work he devoted to electromagnetic design and the development of specific methods for bonded permanent magnets. He is member of the IEEE Magnetics Society, The UK Magnetics Society as well as the International Compumag Society. Thomas has given many lectures at national and international conferences and released a multitude of articles about bonded permanent magnets.
Topic: Injection Molded Magnets for Electrical Machines
Injection molded magnets are applied as rotors and sensor elements for electrical machines in high quantities. In addition to single magnets combined systems are in use with continuously increasing rates for such applications. Injection molded magnets are advantageous in regard to geometry and manufacturing aspects as well as by their high variety of polarization patterns which can be realized. The relatively high amount of magnetic options can be accessed especially when anisotropic magnets are manufactured, as here the anisotropy can be varied inside the magnet by direction and strength. Such magnets typically are made by a process where magnetizing fields are applied directly in the mold. The related fields are originated by assemblies of permanent magnets close to the cavities or by coil systems using DC currents. Magnetic materials for such pole oriented magnets are anisotropic, cost effective Ferrites in most cases. But also by isotropic NdFeB or other rare earth magnets many demands for specific field or force profiles can be satisfied, especially when electrical machines demand a higher flux density. In this case the magnetization is not applied in the mold but by an external pulse magnetizing process. By use of skillfully designed magnetization coils also here tailored pole patterns with a high variety of shapes can be applied.
When injection molded magnets have to be designed it is often possible to cover the whole chain of manufacturing by specific analysis tools. This starts with the material, goes on with the injection molding tool, covers any magnetizing processes and ends with the application itself. The need for such analyses is often originated by the customer who e.g. uniquely specifies field distributions in the air gap between rotor and stator. So impacts like material variations, different magnetic assemblies in the mold or dimensional changes of the magnet have to be studied by their influence on the final application. Our design methods mainly consist of customized static or time transient FEM analyses as well as of analytical methods. In many cases the prediction of polarization distributions is needed, both in pole oriented magnets as well as in pulse magnetized magnets.
The presentation will start with an overview over injection molded magnets including magnetic powders, polymers, tooling and mechanical system aspects. The mentioned design methods will be explained by specific examples of magnets for electrical machines, where results of practical measurements will be compared with predictions of those analyses. Beside rotor magnets also magnets for sensor purposes in EC motors like for commutation or speed detection will be covered. Additionally integrated systems, where different traces for different purposes are combined within one single rotor, will be presented.
Finally the mechanical and physical limitations of bonded magnets for electrical machines as well as the limitations of the design methods will be explained.
Format of Presentation: Power Point
Injection molded magnets are applied for electrical machines in high quantities especially when less power but complex field distributions or geometrical shapes are needed. The magnets are either pole oriented cost effective Ferrites which are magnetized directly in the mold or rare earth magnets which are mainly magnetized by external pulse magnetizing. For an adequate prediction of the magnets behavior specific analysis tools are needed. After an overview over injection molded magnets including materials, tooling and mechanical system aspects, the analysis methods will be explained by practical examples on magnets where predictions from calculations will be compared to measurements.