MW 45x35 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have constant strength, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by external magnetic influence very well,
• The use of a polished silver surface provides a refined finish,
• They possess intense magnetic force measurable at the magnet’s surface,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• With the option for customized forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving application potential,
• Key role in cutting-edge sectors – they are used in hard drives, electric drives, medical equipment as well as technologically developed systems,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of neodymium magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time strengthens its overall strength,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on form). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• They rust in a damp environment, especially when used outside, we recommend using moisture-resistant magnets, such as those made of non-metallic materials,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing threads directly in the magnet,
• Health risk linked to microscopic shards may arise, especially if swallowed, which is crucial in the context of child safety. It should also be noted that miniature parts from these products have the potential to complicate medical imaging if inside the body,
• Due to expensive raw materials, their cost is above average,

Highest magnetic holding force – what affects it?

The given pulling force of the magnet represents the maximum force, measured in a perfect environment, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• at room temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet depends on in practice the following factors, ordered from most important to least significant:

• 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.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, whereas under parallel forces the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet and the plate reduces the load capacity.