China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Inside many electronic products, a type of magnet is used, which are small circular magnets with holes in the middle. These magnets are characterized by their small size and having a through hole or straight hole in the center. The straight round hole is suitable for screws and shafts, while the counterbore can perfectly match with screws.
When it comes to material selection, the type of magnetic material used determines the product’s performance and cost. Sintered neodymium-iron-boron magnets, with their high energy product and strong magnetic pull, are currently the most widely used material. They are particularly suitable for applications requiring compact size and strong holding force, and are easy to machine for both countersunk and through holes. Ferrite magnets, on the other hand, are low-cost and highly corrosion-resistant, making them suitable for applications where magnetic strength is not a top priority but cost is a key consideration. Their drawback is that they require molds for processing. Samarium-cobalt magnets offer good heat resistance and corrosion resistance, and their magnetic strength exceeds that of ferrite magnets, making them suitable for mid- to high-end products that demand high stability and reliability from their magnets.
Small Round Magnet with Hole in Center
Regarding the magnetization method, this type of magnet often adopts axial magnetization, where the upper and lower end faces are respectively marked as N and S poles, suitable for most adsorption applications. For special requirements, radial magnetization can also be employed for functional scenarios such as Hall sensing and motor feedback.
Regarding the machinable dimensions, sintered neodymium-iron-boron materials are characterized by strong magnetic properties, but the material itself is relatively brittle, and the central hole is usually completed through post-processing. An outer diameter of around 3mm is not a problem, and it is generally recommended that the minimum hole diameter not be less than 0.8mm. For sintered ferrite circular magnets with small holes, the common outer diameter range is around Φ5 mm.
When designing small circular magnets with a central hole, try to keep the hole diameter no larger than one-third of the outer diameter. Maintain a wall thickness of at least 0.5 to 1 mm, ensuring that the thickness is no less than the hole diameter. Additionally, avoid sharp corners to reduce the risk of stress concentration. Regarding material selection, if magnetic strength is the primary consideration, choose sintered neodymium-iron-boron.
Selected sample cases;
Small Round Disc Magnet with Hole OD 1.8mm x H 0.8mm N52
Isotropic ferrite radial 2-pole small magnetic ring 5.7x2.2x1.8mm