In magnet applications, magnetic flux or magnetic flux density is crucial for measuring performance, especially in motors. However, in fields like magnetic separation and salvage, magnetic flux isn’t an effective measure for sorting or adsorption. Instead, magnetic attraction force is a more useful indicator.
Magnetic attraction force refers to the weight of ferromagnetic material a magnet can attract. This force is influenced by the magnet’s performance, shape, size, and the distance between the magnet and the attracted material. There isn’t a mathematical formula to calculate the attraction force of a magnet, but we can measure it using a magnetic attraction force measurement device. This typically involves measuring the magnet’s pull force and converting it to weight, as shown in the image below. The attraction force decreases as the distance from the attracted object increases.
We can confirm this through experiments.
The experiment used sintered NdFeB N42 magnets of different shapes and sizes, all with a nickel-copper-nickel coating and magnetized in the thickness direction. The maximum pull force (N pole) of each magnet was measured and converted into the adsorption weight. The results are as follows:
From these results, we can see that:
The ratio of the weight that different shapes and sizes of magnets can attract to their own weight varies greatly. For cylindrical or disc magnets with the same diameter, the greater the height, the greater the weight they can attract, and the attraction force is basically proportional to the height.
For cylindrical or disc magnets with the same height, the larger the diameter, the greater the weight they can attract, and the attraction force is basically proportional to the diameter.
For cylindrical or disc magnets with the same volume and weight but different diameters and heights, the weight they can attract varies greatly. Generally, the longer the orientation direction of the magnet, the greater the attraction force.
Magnets with the same volume do not necessarily have the same attraction force. The attraction force may vary greatly depending on the shape. Conversely, magnets that can attract the same weight of ferromagnetic material may have different shapes, volumes, and weights.
Regardless of the shape, the length of the orientation direction has the greatest impact on the attraction force.
This experiment shows that the design and dimensions of magnets significantly influence their attraction force. Understanding these factors can help in choosing the right magnet for specific applications, ensuring optimal performance and efficiency.
Thank you for reading our article! We hope it aids in your search for the Attraction Force of Sintered NdFeB Magnets. For more information, visit Mainrich Magnets. With over 30 years of expertise and a 98+% quality consistency rate, we offer high-quality rare earth magnets at fair prices. Our customer-centric service and adherence to ISO 9001:2015, RoHS, and REACH standards ensure you get the best. Reach out to discover more.
