FM Ruszt magnetyczny do leja fi 200 dwupoziomowy / N52 - magnetic filter

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They retain their attractive force for almost 10 years – the loss is just ~1% (in theory),
• Their ability to resist magnetic interference from external fields is among the best,
• The use of a polished nickel surface provides a refined finish,
• They have exceptional magnetic induction on the surface of the magnet,
• With the right combination of magnetic alloys, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in various configurations, which expands their application range,
• Significant impact in modern technologies – they are used in computer drives, electromechanical systems, healthcare devices and sophisticated instruments,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They may fracture when subjected to a strong impact. If the magnets are exposed to physical collisions, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time strengthens its overall strength,
• They lose strength at extreme temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the dimensions and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a humid environment – during outdoor use, we recommend using sealed magnets, such as those made of polymer,
• Limited ability to create precision features in the magnet – the use of a mechanical support is recommended,
• Possible threat related to magnet particles may arise, especially if swallowed, which is significant in the health of young users. Furthermore, small elements from these devices might interfere with diagnostics after being swallowed,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Detachment force of the magnet in optimal conditions – what contributes to it?

The given lifting capacity of the magnet represents the maximum lifting force, calculated in ideal conditions, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Key elements affecting lifting force

In practice, the holding capacity of a magnet is affected by these factors, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, as even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.