Injection Molded Magnets

Injection Molded Magnets
Injection Molding Magnet is one of the more important developments in magnetic materials, it has opened a new world of application opportunities. Similar to plastic injection molding, magnet injection molding process is by mixing the magnetic powder (neodymium, ferrite or SmFeN, etc) together with polymer binder (PA6, PA12 or PPS), heated in the injection machine and shooting the melted mixtures into the mold to achieve different shapes of products. The compound can be isotropic material or anisotropic material. The magnetizing fixture design determines the magnetic pattern it requires.

Outstanding Merits

• Complex shapes
• High precision
• Over molding or insert molding is an ideal method to offer good solution to achieve assembly in one step without a secondary assembly process.
• NdFeB, Ferrite, SmFeN, etc wide range of material options
• Hybrid versions as well (e.g. Ferrite+NdFeB) with combined properties

Injection Molded Neodymium
Magnetic powder of injection molded neodymium magnet is neodymium-iron-boron (NdFeB), either isotropic or anisotropic. And Polymer binders are normally PA12 or PPS. Injection molded neodymium has an excellent magnetic performance, but it costs higher due to rare earth utilized. Hybrid magnetic powder combinations are also options for more choices, for example, the combination of NdFeB and Ferrite, etc.

Merits of injection molded NdFeB

•Magnetic powder is neodymium-iron-boron (NdFeB), either isotropic or anisotropic. And Polymer binders utilized are PA12 or PPS, maximum operation temperature 120℃.

•Anisotropic NdFeB powder achieves the highest magnetic force as injection molded magnet. And it is possible to achieve above BHmax 10GMOe.

Injection Molded Ferrite
Injection molded ferrite magnet is another molding process of magnet category, the compound is ferrite mixed with binder PA6, PA12 or PPS, binder selection depends on the application condition. Injection molded ferrite offers lower magnetic performance than that of injection molded neodymium. But injection molded ferrite costs much lower than that of neodymium and widely applied in industry.

Merits of injection molded ferrite

•Magnetic powder is ferrite, either isotropic or anisotropic. And Polymer binders utilized are PA6, PA12 or PPS, maximum operation temperature 120℃.

•Cost effective solution

Injection Molded SmFeN Injection molded SmFeN is a relatively new application in industry with technology development. The compound is Samarium-Iron-Nitrogen (Sm-Fe-N) at certain percentage of each and mixed together with binder PA12. As element Samarium is introduced, it shows excellent thermal coefficient. The hybrid of NdFeB and SmFeN posses great performance of higher magnetic properties and thermal coefficient, which opens a door to wide and new applications.

Merits of injection molded SmFeN

•Excellent Thermal Coefficient

•Great magnetic performance

•Different type of hybrids for wider application solution.

Injection Magnetic Assemblies Insert Molding (over molding) is a subset of injection molding techniques where metal, plastic or magnet are placed into a mold cavity before the actual injection. The insert is precisely positioned inside the mold either manually or by a robotic arm. The mold then closes, and plastic or magnet is molded over the insert, creating a single part.

Merits of magnetic assemblies:

•Increased Material Flexibility - It allows designers to leverage the benefits of multiple types of materials to create complex parts with different properties, add visual complexity, or add haptics.

•No Adhesives Required - It allows different materials to be fused in the mold, thus eliminating the need for glues or other permanent bonding methods. This increases the part's overall durability and reduces assembly costs.  

•Reduced Assembly Cost - An injection molding machine can create thousands of parts per day. Such economies of scale can significantly reduce the cost of the individual parts. In a typical CNC machined, sheet metal, or additive manufactured part, any required assembly can be a major bottleneck. Insert/over molding can be used to eliminate assembly and thus maximize cost savings.

Injection Molded Magnets are widely used as high-end magnetic materials because they can be made into complex shapes and have high precision. They're mainly used in cars, office automation, and power transmission, with specific products including: micro machine, printers, actuators, location sensor, buzzer, brushless motors for automotive and home appliance industry.

Compression Bonded Magnets