Introduction
Injection molded magnets provide a diverse range of magnetic properties, including ferrite, neodymium-iron-boron, SmCo, and SmFeN options. These magnets can be combined with binder types such as Nylon 6, Nylon 12, and PPS, enabling a wide application temperature range from -40°C up to 160°C.
The injection molding process is highly suitable for creating complex shapes and thin-walled parts, offering new design possibilities for magnets and magnetic systems. This includes the production of thin rings, non-magnetized mechanical components, and more. Additionally, injection molding allows magnets to be molded over metallic or polymer components (insert molding) or integrated into normal plastic, enabling the manufacture of complete assemblies in one or two process steps. This process offers versatility and efficiency in magnet manufacturing.
Magnetic properties
The properties of injection molded magnets are influenced by the specific combination of magnetic material and binder utilized. Table 1 and 2 provide typical properties for each grade at room temperature. It is worth noting that the actual properties of a finished magnet may vary from the material properties due to factors such as magnet geometry and magnetization process. The inherent limitations of injection molded magnet geometry often make it challenging to control properties through standard methods like BH-curve tracking.
As a result, it is crucial to establish agreed-upon quality assurance (QA) methods to ensure consistent performance and meet desired specifications for injection molded magnets. These QA methods should account for the unique characteristics and manufacturing constraints associated with injection molded magnet production.
Design Considerations
It is true that the magnetic properties of bonded magnets are generally lower compared to fully dense magnets made of the same material. Similarly, the temperature properties of bonded magnets may also be inferior. However, the advantage of bonded magnets lies in their versatility for designing magnets with complex shapes, thin walls, multipole magnetization, and functional details. These design possibilities often outweigh the decrease in pure magnetic power.
Bonded magnets offer flexibility and the ability to create intricate magnet geometries that may not be achievable with fully dense magnets. This opens up a wide range of applications where specific magnet shapes and features are crucial. While bonded magnets may have lower magnetic properties, their unique design capabilities make them a valuable choice in various industries and applications.
