MPL 5x5x2 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They have constant strength, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by surrounding electromagnetic environments effectively,
• The use of a polished gold surface provides a eye-catching finish,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for custom shaping or customization to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which amplifies their functionality across industries,
• Key role in new technology industries – they serve a purpose in HDDs, rotating machines, clinical machines or even high-tech tools,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, in miniature format,

Disadvantages of magnetic elements:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to shocks, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from damage and enhances its overall durability,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent loss 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,
• Magnets exposed to moisture can degrade. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is not feasible,
• Safety concern from tiny pieces may arise, when consumed by mistake, which is significant in the protection of children. Additionally, tiny components from these assemblies might disrupt scanning when ingested,
• In cases of mass production, neodymium magnet cost may be a barrier,

Maximum lifting force for a neodymium magnet – what contributes to it?

The given pulling force of the magnet represents the maximum force, determined in ideal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• under standard ambient temperature

Lifting capacity in real conditions – factors

Practical lifting force is dependent on elements, 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.

* Lifting capacity was measured with the use of a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.