What are Magnetic Materials?
Magnetic material is an ancient and novel functional material. The magnetic material itself has many special properties. It is precisely based on these properties that the magnetic material can complete the mutual conversion between external physical quantities and magnetic signals, thus making various types of magnetic devices. As magnetic functional devices develop toward intelligence, miniaturization, multi-function, high sensitivity, low power consumption, and high reliability, the types of new magnetic functional devices are also increasing rapidly, and their application scenarios are becoming broader.
Introduction to Injection Molded Magnets
Injection molded magnets are magnets produced by mixing magnetic powder, resin (PA6, PA12, PPS, etc.), additives, and other materials, and using a special injection molding machine through injection molding. Injection-molded magnets have strong magnetism and can be used in various injection-molded products that require magnetism, such as motors, sensors, fans, toys, etc.
The advantage of injection molded magnets is that they can be closely combined with other materials through the injection molding process to form a whole, thus improving the stability and reliability of the product. In addition, injection molded magnets can also be customized according to different needs, such as different shapes, sizes, magnetic strengths, etc., to meet the needs of different products.
The performance of injection molded magnets mainly depends on the magnetic powder material. Of course, it is also closely related to the resin used, the filling rate of the magnetic powder, and the molding processing method. Technical indicators for evaluating magnetic plastics include residual magnetic flux density Br. Coercive force bHc, intrinsic coercive force jHc, and maximum magnetic energy product (B·H)max.
Injection Molding Material Characteristics
Plastic magnetic material PA6
Features: high fluidity, medium magnetic properties, low cost
Application: Mainly used in printer magnetic rollers, motor rotors for home appliances, miniaturized motor rotors, automobile micromotor rotors, and other components
Typical grade: TMF6-140
Plastic magnetic material PA12
Features: high fluidity, medium magnetic properties
Application: Mainly used in printer magnetic rollers, motor rotors for home appliances, miniaturized motor rotors, automobile micromotor rotors, and other components
Typical grade: TMF12-195
Plastic magnetic material PPS
Features: High heat resistance, flame retardant, high fluidity, high magnetic properties
Application: Mainly used in printer magnetic rollers, miniaturized motor rotors, automobile micromotor rotors, and other components
Typical grade: TMF6-140
Characteristics of Injection Molded Magnets
1. The characteristic of injection molded magnets is that they can be axially unipolar magnetized, radially multi-stage magnetized, or axially and radially composite magnetized.
2. The product has the advantages of smooth and flawless appearance, high dimensional accuracy, good consistency, lightweight, thin wall, complex shape, no need for subsequent processing, stable performance, earthquake resistance, and impact resistance, and the product can be complicated. It is an ideal choice for the precision micromotor and automation industry It is an indispensable signal source and constant magnet source and has advantages that other magnets cannot replace and compare with.
3. Injection molding has stable magnetic properties and can be injection molded together with other metal parts. Nowadays, injection molded magnets can meet the requirements of many precision, lightweight, and high-performance electronic products, which is a condition that is difficult to achieve with sintered magnets.
If an axial or radial external magnetic field is applied to injection molded magnets during the molding process, magnets with higher magnetic properties can be obtained.
Comparison Between Injection Molded Magnets and Sintered Magnets
1. Production process
*Injection molding permanent magnet: The process is simple, it can be injection molded with various metal and non-metal inserts, and multiple composite moldings can be performed.
*Sintered permanent magnets: The process flow is complicated, and assembly with other metal inserts requires additional procedures.
Advantages of injection molded magnetic contrast: lower production and assembly costs.
2. Magnetic properties
*Injection molded permanent magnet: high surface magnetic field performance.
*Sintered permanent magnet: The surface magnetic field performance is very high.
Advantages of injection molded magnetic contrast: stable performance, effectively improving motor performance.
3. Reliability
*Injection molded permanent magnet: The product has high toughness, strong mechanical properties, and is not easy to break and chip.
*Sintered permanent magnet: The product has high strength, but is brittle and easy to break, chip, and collapse.
Advantages of injection molded magnetic contrast: greatly increase the service life and reliability of the motor.
4. Dimensional accuracy
*Injection molding permanent magnet: Adopt the injection molding method, with high precision, good product consistency, and high operating balance
*Sintered permanent magnets: Using the sintering molding method, the product accuracy is poor. When assembled with other inserts, the product operation balance is not high.
Advantages of injection molded magnetic contrast: high product consistency, stable quality, and guaranteed motor quality.
5. Multipolarization
*Injection molded permanent magnet: It can be molded into any multi-polar product at one time without reducing the surface magnetism.
*Sintered permanent magnets: The coil magnetization method is used, the process is complicated, the more poles the higher the cost, the accuracy is poor, and the magnetism is difficult to control.
Advantages of injection molded magnetic contrast: greatly improve the freedom of motor design.
Main Applications of Injection Molded Magnets
Injection-molded magnets are widely used as high-end magnetic materials because they can be processed into complex shapes and have high precision. They are mainly used in automobiles, office automation, transmission, and other fields. Specific products include:
Injection molded magnetic tiles: used in various types of micro motors. They are characterized by radial orientation, high magnetic flux efficiency, not fragile, and do not shed chips. Micromotors with starting voltage requirements can be started at low voltage.
Laser printer magnetic core: It is characterized by one-piece molding, high orientation, and good unipolar uniformity, reaching the current technical level of similar foreign products.
Sensor magnets: widely used in precision sensor fields such as various types of automobile regulating motors, household appliance motors, OA equipment, and cylinders.
Rotor magnets: Mainly used in brushless DC motors such as air conditioners, household appliances, rotors of synchronous motors, and magnetic couplers. Can be injection molded integrally with the shaft.
- Magnetic rollers for laser printers, copiers, and fax machines
- Motor stator and rotor
- Sensor magnets and assemblies
- Magnetic coupling assembly
- Precision measuring instruments
- Home appliances, office automation equipment, communications, national defense, aviation, navigation and other fields