MPL 10x7x3 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their remarkable pulling force, neodymium magnets offer the following advantages:

• They do not lose their power nearly ten years – the decrease of lifting capacity is only ~1% (theoretically),
• They are highly resistant to demagnetization caused by external magnetic fields,
• Thanks to the shiny finish and nickel coating, they have an visually attractive appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in various configurations, which broadens their usage potential,
• Significant impact in modern technologies – they are used in hard drives, electromechanical systems, healthcare devices or even technologically developed systems,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of magnetic elements:

• They can break when subjected to a strong impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall resistance,
• High temperatures may significantly reduce the holding force 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,
• They rust in a wet environment – during outdoor use, we recommend using sealed magnets, such as those made of polymer,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing threads directly in the magnet,
• Health risk due to small fragments may arise, when consumed by mistake, which is notable in the family environments. It should also be noted that tiny components from these devices may interfere with diagnostics if inside the body,
• Due to expensive raw materials, their cost is relatively high,

Detachment force of the magnet in optimal conditions – what affects it?

The given holding capacity of the magnet represents the highest holding force, calculated in ideal conditions, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• at room temperature

Practical aspects of lifting capacity – factors

In practice, the holding capacity of a magnet is affected 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 measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.