Injection Magnet Has A Strong Anti-corrosion Ability

What is injection magnets? Injection of magnets, is the magnetic powder and binder mixing granulation, and then through the injection molding process made of permanent magnets known as injection magnets. Compared to other methods of making permanent magnets, injection molding has a unique and irreplaceable advantage. First of all, and plastic products, injection molding can produce complex shape of the magnet. In addition, the injection molding process can be "embedded molding", "multi-step molding", "multi-workpiece molding" way to combine the magnets and other parts of the molding, thus saving the cost of secondary processing and assembly. Injection molding technology can produce isotropic magnets and can produce anisotropic magnets. Anisotropic magnets need to add an orientation magnetic field in the molding process, so that the magnetic powder in the molten state of the polymer has a certain bit direction, that is, orientation, and can achieve multi-pole magnetization. Injection molding process makes the product in the size and performance on a better consistency. In the molding process, the material in the strong injection pressure to the highest concentration of the mold cavity was completely filled, coupled with the material containing thermoplastic adhesive, the magnet to obtain a good physical and mechanical properties. Due to the high content of the polymer binder in the injection magnet, the magnet itself has a strong corrosion resistance and is usually not required for surface coating protection.

With its own unique advantages, injection magnets are often used in: small power DC motor magnetic stator, brushless DC and stepper motor multi-pole magnetic rotor, magnetic drive, automotive and other industrial sensors and other products.

Injection magnets generally use nylon 6, nylon 12 and PPS these kinds of thermoplastic adhesives. For any particular application, the choice of binder is based on a number of factors including temperature characteristics, strength, water absorption, solvent resistance, magnet shape complexity, and compatibility with magnetic powder.

Temperature characteristics: injection molding magnet maximum temperature depends on the use of its magnetic powder and binder. For example, ferrite powders can be combined with nylon 6 or PPS by 180 ° C. And the nylon 12 melts at 170 ° C or higher, the nylon 12 is not recommended if the magnet design temperature exceeds 150 ° C. In the case of NdFeB powder with a high energy product, if its intrinsic coercivity is 9500 oersteds (760 kA / m), no matter what kind of binder, at more than 120 ° C, Magnetic properties will be significant irreversible loss.

Dimensional accuracy: As the injection molding products in size and injection mold cavity consistent, so the product size accuracy can be controlled relatively high. In addition, the binder in the material when the shrinkage occurs when the cooling will result in product size changes, the degree of contraction depends on the thickness and shape of the product. Typical dimensional tolerances are: ± 0.05mm.