MPL 25x12.5x5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their notable power, neodymium magnets have these key benefits:

• They retain their magnetic properties for almost 10 years – the drop is just ~1% (based on simulations),
• They protect against demagnetization induced by surrounding magnetic fields very well,
• The use of a decorative gold surface provides a refined finish,
• Magnetic induction on the surface of these magnets is impressively powerful,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the design),
• The ability for precise shaping as well as adjustment to individual needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Significant impact in cutting-edge sectors – they are utilized in computer drives, electric drives, clinical machines along with other advanced devices,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to physical collisions, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks and enhances its overall resistance,
• They lose field intensity at high temperatures. Most neodymium magnets experience permanent degradation 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,
• Magnets exposed to wet conditions can oxidize. Therefore, for outdoor applications, it's best to use waterproof types made of coated materials,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing holes directly in the magnet,
• Safety concern linked to microscopic shards may arise, when consumed by mistake, which is notable in the health of young users. Furthermore, miniature parts from these products can disrupt scanning once in the system,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which may limit large-scale applications

Highest magnetic holding force – what contributes to it?

The given strength of the magnet means the optimal strength, assessed in the best circumstances, that is:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• under perpendicular detachment force
• under standard ambient temperature

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, as 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 the force acted perpendicularly, in contrast under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate lowers the load capacity.