MPL 30x20x10 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They do not lose their even over approximately 10 years – the decrease of power is only ~1% (theoretically),
• Their ability to resist magnetic interference from external fields is among the best,
• Thanks to the polished finish and nickel coating, they have an elegant appearance,
• Magnetic induction on the surface of these magnets is very strong,
• 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 targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
• Important function in cutting-edge sectors – they are utilized in hard drives, electric motors, clinical machines or even technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, 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 mechanical hits, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage and additionally reinforces its overall robustness,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent decline 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 wet environment – during outdoor use, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create threads in the magnet – the use of a housing is recommended,
• Health risk from tiny pieces may arise, if ingested accidentally, which is significant in the health of young users. Furthermore, small elements from these devices have the potential to disrupt scanning if inside the body,
• Due to the price of neodymium, their cost is relatively high,

Maximum holding power of the magnet – what affects it?

The given pulling force of the magnet corresponds to the maximum force, measured in a perfect environment, specifically:

• with the use of low-carbon steel plate acting as a magnetic yoke
• with a thickness of minimum 10 mm
• with a polished side
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Determinants of lifting force in real conditions

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

• 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 the plate surface of 20 mm thickness, when a perpendicular force was applied, however under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate reduces the load capacity.