Analysis of Two-Track Injection-Molded Magnetic Ring Technology

Micron-Level Precision! Two-Track Injection-Molded Magnetic Ring: The "Invisible Champion" in the Sensor Field

In the realm of precision measurement and control, a seemingly small yet crucial component is quietly pushing the limits of high-performance systems—the two-track injection-molded magnetic ring. With its unique advantages of micron-level tolerance precision and tight assembly with shafts, this technology has become an indispensable core component in high-end industrial, automotive electronics, and precision instrumentation.

What is a Two-Track Magnetic Ring?

As the name suggests, a two-track magnetic ring features two independent magnetic signal tracks formed simultaneously on a single ring through precision injection molding. These tracks are typically arranged with different pole-pair numbers or encoding methods. They can synchronously output position and speed information, and even enable multi-turn absolute position measurement, providing dual data assurance for complex motion control.

Why is Micron-Level Tolerance Critical?

In high-speed rotation or precision positioning applications, even the slightest dimensional deviation can lead to signal distortion, measurement errors, or even system failure.

• 1/70th of a Human Hair: Micron-level tolerance means dimensional accuracy is controlled within 1-10 micrometers, equivalent to 1/7th to 1/70th the diameter of a human hair. This precision ensures the consistency and stability of the magnetic signal cycle.

• Eliminating Signal Jitter: Extremely low radial and axial runout tolerances allow the magnetic ring to output smooth, low-noise signals even during high-speed operation, significantly improving the system's signal-to-noise ratio.

• Ensuring Interchangeability: High-precision manufacturing guarantees part interchangeability, eliminating the need for individual calibration during batch assembly, thereby greatly enhancing production efficiency and product consistency.

Injection Molding Process: The Perfect Fusion of Precision and Strength

Traditional magnetic rings often use bonded magnetic powder or split assembly methods, which face bottlenecks like insufficient strength, delamination risk, or poor concentricity. Injection molding technology achieves a revolutionary breakthrough by directly forming magnetic material and engineering plastic in a molten state:

• Flawless Structure: The magnet and substrate bond at a molecular level without adhesive interfaces, completely eliminating the risk of detachment. This is especially suitable for high-speed, high-vibration environments.

• One-Step Molding of Complex Structures: Features like dual tracks, positioning bosses, and assembly clasps can be precision-formed in a single step. This reduces subsequent processing, lowers costs, and avoids secondary errors.

• Optimized Material Performance: The molding substrate can be made from special engineering plastics that are temperature-resistant and corrosion-resistant, allowing the magnetic ring to withstand operating environments from -40°C to 150°C or even harsher conditions.

Tight Assembly with Shafts: More Than Just a "Press Fit"

The final performance of a magnetic ring heavily depends on the quality of its assembly onto the rotating shaft. Advanced design ensures that assembly is both a physical bond and a performance guarantee:

• Scientific Calculation of Interference Fit: Finite element analysis simulates deformation under various temperatures and speeds to optimize the interference level, ensuring no loosening occurs even under extreme conditions.

• Intelligent Anti-Misalignment Design: Integrated keyways, asymmetric tabs, or laser markings prevent assembly angle errors, ensuring accurate phase alignment of the two tracks.

• Stress-Free Assembly Process: Techniques like thermal assembly or specialized tooling are used to avoid impact damage to the magnet or internal stress, preserving the original signal accuracy.

Application Scenarios: Empowering High-Tech Fields

• Automotive Electric Power Steering: Dual tracks provide redundant signals, meeting the highest functional safety level (ASIL D), ensuring precise and safe steering.

• Industrial Robot Joints: Micron-level precision enables sub-degree joint positioning, resulting in smooth and accurate robot movements.

• Drone Gimbal and Motors: Tight assembly withstands high-frequency vibrations, maintaining stable images and controllable flight in dynamic environments.

• High-End Medical Equipment: Provides quiet and reliable position feedback in CT scanner rotating components and surgical robots.

Future Outlook and Technology Implementation

As the trends of electrification, automation, and intelligence advance, the demands on sensor accuracy and reliability will become increasingly stringent. Two-track injection-molded magnetic ring technology is evolving towards higher precision, smaller size, and stronger environmental adaptability.

It is encouraging to note that this cutting-edge technology has successfully achieved industrial application. The micron-tolerance two-track injection-molded magnetic ring independently developed by SDM has officially entered production. This product perfectly integrates the aforementioned precision molding, dual-track integration, and tight assembly technologies, achieving mass-production assurance of high performance and high reliability. It provides a solid solution for the development of domestic core components for precision sensors.

Precision begins at the microscopic level and enables system-level achievement. From theoretical breakthrough to industrial implementation, the two-track injection-molded magnetic ring, though hidden within equipment, vividly demonstrates how extreme micro-manufacturing precision can leverage macro-system performance leaps. It is not only a cornerstone of modern precision engineering but also marks a solid step forward in our independent innovation and manufacturing capabilities in the field of core precision components.