Plastic-bonded magnets are particle composites with permanent-magnet powder embedded in a plastic binder. Hard ferrite (HF), various SmCo and NdFeB powders and, to a very little extent, AINiCo alloys are used as magnetic powder. For embedding the magnetic particles, thermoplastic binders as, for instance, polyamide (PA) or polyphenyl sulfide (PPS) and duroplasts like epoxy resins are used. Depending on the material composition and production process, isotropic and anisotropic magnets with differing magnetic and mechanical specifications are available. Since not only the type of magnet or plastic material, but the filling and alignment degree, too, determine the composite's properties, the outcome is widely varying magnetic parameters and an outstanding variety in types and shapes.
The rigid plastic-bonded magnets have two production processes. Injection molding is the most frequently used. Compression molding is used especially for plastic-bonded rare-earth magnets.
First of all, a compound is mixed from the magnet powders and plastics. In the injection-molding process, hard ferrite or rare-earth powders are embedded into thermoplastics and granulated. The granulate is processed on injection-molding machines into magnet moldings. In compression molding technology, only of economic relevance for manufacturing plastic-bonded rare-earth magnets, suitable powder mixtures are processed in tools and presses. NdFeB powder is combined with duroplastic resins. In the compression tools, the compound mixtures are subsequently molded into the most frequently used shapes as blocks, disks, rings, flat sections and segments. After shaping, a thermal hardening phase follows, making the pressed material mechanically stable. This is followed by the finishing and surface cleaning stages. Depending on customer demands, the parts are magnetized and the surface marked or coated.
Plastic-bonded hard ferrite magnets
Plastic-bonded NdFeB magnets
Our Product Range:
Our range comprises a wide selection of plastic-bonded hard ferrite and NdFeB materials with differing magnetic properties. They permit material selection tailored to individual application requirements.
|Product info Plastic-bonded hard ferrite magnets||PDF (1.9MB)|
|Product info Plastic-bonded REFeB magnets||PDF (1.7MB)|