Automotive air conditioning damper actuators (damper motors) are key components controlling the opening/closing of air ducts and air direction adjustment, requiring high precision, low noise, and long service life. Injection molded magnets play a significant role in the gearbox and motor sections within this application.

Core Advantages:

• High Precision & Complex Shapes: Enables precise molding of multi-pole magnetic rings or gears for gear transmission, with high accuracy in tooth profile and pole position, ensuring accurate actuator positioning.

• Low-Noise Operation: The inherent damping characteristics of injection molded magnets help reduce impact noise during gear transmission, enhancing driving comfort.

• Wear Resistance & Long Life: Engineering plastic binders impart good wear resistance to the magnetic components, making them suitable for long-term, frequent gear meshing movements.

• Design Integration: Allows for the integration of multiple functional structures like bearing housings and gears into a single injection-molded part, reducing the number of components and improving assembly efficiency and quality.

Core Manufacturing Process Flow:

1. Material Selection & Preparation

   • Magnetic Powder: Strontium ferrite (Sr-Ferrite) is commonly used due to its lower cost and good corrosion resistance, meeting actuator requirements for torque and life. Neodymium Iron Boron (NdFeB) is used where higher dimensional and performance requirements exist.

   • Binder: Polyphenylene sulfide (PPS) and Nylon (PA) are mainstream choices, providing good mechanical strength, heat resistance, and dimensional stability to withstand high-temperature environments within the vehicle cabin.

   • Mixing & Pelletizing: Precise proportioning and uniform mixing are essential for ensuring consistent magnetic properties and gear dimensional accuracy.

2. Precision Injection Molding

   • Mold Technology: Magnetic gears in damper actuators demand extremely high mold precision. Cavity and ejector pin design must ensure product dimensional stability and smooth demolding, avoiding issues like burrs or flash that affect gear meshing.

   • Molding Control: Precise control of melt temperature, injection speed, holding pressure, and cooling time during injection molding is critical for minimizing product shrinkage, deformation, internal stress, and warpage, directly impacting gear transmission accuracy and smoothness.

3. Magnetization

   • The magnets in actuators typically serve as the motor rotor or signal source for position sensors, requiring multi-pole magnetization. The accuracy of the magnetization pattern decisively influences motor control precision and sensor feedback signal accuracy.

4. Inspection & Assembly

   • Dimensional & Geometric Tolerance Inspection: Using optical projectors, coordinate measuring machines (CMM), etc., to inspect key gear dimensions such as tooth profile, pitch, and concentricity.

   • Magnetic Performance Testing: Ensuring magnetic field strength and pole angle meet design requirements.

   • Gear Performance Testing (Optional): Noise, torque, and life tests may be conducted in some cases.

Process Challenges & Requirements:

• Stringent Dimensional Tolerances: Minor deviations in gears can lead to actuator jamming, abnormal noise, or positioning inaccuracy.

• High Durability: Products must withstand tens of thousands or even hundreds of thousands of cycles without failure, demanding high material wear resistance and fatigue strength.

• Environmental Resistance: Must withstand severe temperature fluctuations within the vehicle cabin (-40°C to 85°C or higher), as well as vibrations, chemicals, and other influences.

Summary

Injection molded magnet components for automotive damper actuators are typical precision parts. Their manufacturing process encompasses high-precision mold design, stable injection molding, precise multi-pole magnetization, and strict inspection. This places high demands on the comprehensive technical capabilities of magnet suppliers. Suppliers within the industry, such as Ningbo Buji Magnetic-Electronic Technology Co., Ltd., leveraging their diverse product portfolio in binders (PPS/PA) and magnetic powders (NdFeB/Ferrite) along with component integration experience, are capable of participating in and supporting damper actuator manufacturers in developing highly reliable and cost-effective solutions.