MPL 25x2x6 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their tremendous magnetic power, neodymium magnets offer the following advantages:

• They retain their magnetic properties for almost ten years – the loss is just ~1% (according to analyses),
• They protect against demagnetization induced by ambient magnetic fields remarkably well,
• By applying a shiny layer of gold, the element gains a clean look,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• Thanks to their exceptional temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• The ability for custom shaping and customization to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Important function in modern technologies – they are used in HDDs, electric drives, healthcare devices and technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to shocks, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time reinforces its overall robustness,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on size). 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,
• Magnets exposed to moisture can oxidize. Therefore, for outdoor applications, it's best to use waterproof types made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing threads directly in the magnet,
• Safety concern due to small fragments may arise, in case of ingestion, which is notable in the family environments. Moreover, miniature parts from these assemblies have the potential to interfere with diagnostics if inside the body,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting capacity of the magnet – what contributes to it?

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

• with mild steel, used as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• Air gap between the magnet and the plate, because 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 measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.