MPL 30x20x20 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after ten years, the performance loss is only ~1% (based on calculations),
• They protect against demagnetization induced by ambient magnetic fields very well,
• Thanks to the shiny finish and nickel coating, they have an aesthetic appearance,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• Thanks to the possibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in various configurations, which increases their usage potential,
• Important function in cutting-edge sectors – they are utilized in computer drives, electric motors, medical equipment or even high-tech tools,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to shocks, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from damage and increases its overall robustness,
• They lose power at extreme temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to moisture can degrade. Therefore, for outdoor applications, we advise waterproof types made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing holes directly in the magnet,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is notable in the context of child safety. Additionally, tiny components from these magnets may disrupt scanning when ingested,
• Due to a complex production process, their cost is considerably higher,

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

The given pulling force of the magnet means the maximum force, calculated in the best circumstances, specifically:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• under standard ambient temperature

Key elements affecting lifting force

In practice, the holding capacity of a magnet is affected by the following aspects, arranged from the most important to the least relevant:

• 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.

* Lifting capacity was assessed by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.