BM 510x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They have stable power, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They remain magnetized despite exposure to magnetic surroundings,
• Because of the brilliant layer of nickel, the component looks visually appealing,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• With the right combination of compounds, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the structure),
• The ability for accurate shaping as well as adaptation to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Significant impact in modern technologies – they are utilized in hard drives, electric drives, healthcare devices as well as other advanced devices,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time enhances its overall robustness,
• They lose power at high temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we suggest waterproof types made of coated materials,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing fine shapes directly in the magnet,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is significant in the family environments. Additionally, small elements from these devices have the potential to complicate medical imaging when ingested,
• Due to expensive raw materials, their cost is considerably higher,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The given strength of the magnet means the optimal strength, measured in the best circumstances, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• with vertical force applied
• under standard ambient temperature

Lifting capacity in practice – influencing factors

In practice, the holding capacity of a magnet is affected by these factors, in descending order of importance:

• Air gap between the magnet and the plate, since 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, however under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate decreases the load capacity.