KM HF - 22 kg - magnetic bracket

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for almost 10 years – the drop is just ~1% (based on simulations),
• Their ability to resist magnetic interference from external fields is notable,
• The use of a polished silver surface provides a eye-catching finish,
• Magnetic induction on the surface of these magnets is notably high,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Thanks to the flexibility in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in diverse shapes and sizes, which expands their application range,
• Significant impact in advanced technical fields – they find application in hard drives, electric drives, clinical machines as well as high-tech tools,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to external force, it is suggested to place them in a metal holder. The steel housing, in the form of a holder, protects the magnet from cracks and enhances its overall robustness,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent decline in performance (depending on height). 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,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of plastic for outdoor use,
• Limited ability to create threads in the magnet – the use of a external casing is recommended,
• Health risk from tiny pieces may arise, if ingested accidentally, which is important in the family environments. Furthermore, small elements from these assemblies have the potential to disrupt scanning after being swallowed,
• Due to expensive raw materials, their cost is relatively high,

Highest magnetic holding force – what affects it?

The given strength of the magnet represents the optimal strength, determined in ideal conditions, that is:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Determinants of lifting force in real conditions

Practical lifting force is determined by factors, by priority:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) can cause 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 tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.