Magnets in smartwatches are essential components, playing a crucial role in their normal operation. Since neodymium magnets are the most widely used magnets in smartwatches, this article will focus on the use of neodymium magnets in smartwatches.
Types of Magnets in Smartwatches
The primary magnets in smartwatches are neodymium-iron-boron and samarium-cobalt magnets, with samarium-cobalt magnets being less common.
| Neodymium-Iron-Boron Magnets (NdFeB): Neodymium-iron-boron magnets are critical materials for achieving multifunctional integration in smartwatches due to their high magnetic performance, miniaturization, and stability, making them the most widely used type of magnet in smartwatches.
Neodymium-iron-boron magnets are currently the strongest permanent magnetic materials available, with extremely high magnetic energy product and coercivity. They are capable of generating strong magnetic fields while being compact and lightweight, making them suitable for the limited space in smartwatches. They are commonly found in components such as vibration motors, wireless charging alignment magnets, and heart rate sensor isolation magnets, enabling precise tactile feedback, efficient wireless charging, and reduced sensor signal interference.
| Samarium-Cobalt Magnets (SmCo): Samarium-cobalt magnets possess a high magnetic energy product and good temperature stability, maintaining magnetic stability in higher temperature environments. However, they are more expensive and relatively brittle. Samarium-cobalt magnets are less frequently used in smartwatches, but they may be chosen for high-end models that require greater temperature stability, especially in high-temperature applications.
Role of Magnets in Smartwatches
| Wireless Charging Alignment: Neodymium-iron-boron magnets are used in the wireless charging module of smartwatches to ensure precise alignment between the watch and the charger through magnetic attraction principles, enhancing the efficiency and stability of wireless charging. For example, brands like Samsung optimize the layout of magnets to achieve a tight adhesion between the charging coil and the smartwatch, reducing energy loss.
| Vibration Feedback: In vibration motors, magnets in smartwatches provide a stable magnetic field, allowing the energized coil to vibrate under the magnetic field, generating tactile feedback. This vibration can be used in notifications and other scenarios, with high-performance characteristics ensuring quick vibrational response and precise force.
| Acoustic Module Assistance: In some smartwatch speaker or microphone modules, neodymium-iron-boron magnets assist in the electromagnetic induction process, helping to convert electrical signals into sound signals or aiding in sound collection and transmission, thereby improving audio quality.
Why Neodymium Magnets Are the Most Common in Smartwatches
| Magnetic Performance: Neodymium-iron-boron magnets are among the strongest permanent magnetic materials, with a magnetic energy product (BHmax) significantly exceeding that of other common magnets (such as ferrites and alnico). This allows them to generate a stronger magnetic field in a smaller volume, achieving efficient magnetic energy conversion.
| Miniaturization: Due to their high magnetic energy product, neodymium-iron-boron magnets can dramatically reduce size and weight without sacrificing performance. They provide a powerful magnetic force within the limited space of smartwatches, effectively enhancing efficiency and portability.
| Cost-Effectiveness: Compared to other high-performance magnets (such as samarium-cobalt), the raw material cost for neodymium-iron-boron magnets is lower, and their manufacturing processes are well-established, making large-scale production more cost-effective. This helps reduce the overall cost of smartwatches while meeting performance requirements.
Protection of Magnets in Smartwatches
To ensure the stable performance of Neodymium magnets in smartwatches, various protective measures are necessary.
| Sealed Housing: Neodymium magnets are encapsulated within the smartwatch casing, using the waterproof features of the housing to prevent exposure to external environments (such as sweat, moisture, and dust). The materials for the casing are typically corrosion-resistant and wear-resistant metals or plastics, and sealing is enhanced with gaskets or sealants to ensure tightness.
| Electroplating Coating: Metal layers, such as nickel, zinc, or copper, are deposited on the surface of the magnets through electroplating processes. Nickel plating is the most common method, effectively isolating the magnets from air and moisture, which improves corrosion resistance and wear resistance. Multi-layer electroplating (e.g., nickel-copper-nickel structure) can further enhance protective effects without affecting magnetic performance.
| Avoiding High Temperature and Humidity: Neodymium magnets in smartwatches can experience performance degradation and corrosion in high-temperature or high-humidity environments, so it is essential to avoid prolonged exposure of the smartwatch to direct sunlight, high temperatures, or moist environments.
Magnets Manufacturer
At Tengye, we’re thrilled to be early participants in your new projects. Our passion for magnets extends from material selection and design optimization to providing magnetic solutions. We hope to bring our knowledge and experience to the forefront by actively engaging in your upcoming projects. Work with our magnet experts to get the right magnet solution.
Image Source: Cincinnatiwatch & Ifixit & Masetec & Gearpatrol & Sciencedirect & Stanfordmagnets
