MPL 6x6x6 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have constant strength, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the brilliant layer of gold, the component looks aesthetically refined,
• They possess intense magnetic force measurable at the magnet’s surface,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• Thanks to the flexibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in different geometries, which expands their functional possibilities,
• Important function in modern technologies – they serve a purpose in computer drives, electromechanical systems, healthcare devices and sophisticated instruments,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of rare earth magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to shocks, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time increases its overall durability,
• They lose strength at extreme temperatures. Most neodymium magnets experience permanent loss 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,
• Due to corrosion risk in humid conditions, it is wise to use sealed magnets made of rubber for outdoor use,
• Limited ability to create internal holes in the magnet – the use of a mechanical support is recommended,
• Health risk from tiny pieces may arise, if ingested accidentally, which is important in the health of young users. Moreover, small elements from these assemblies can disrupt scanning once in the system,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting capacity of the magnet – what it depends on?

The given holding capacity of the magnet means the highest holding force, determined in the best circumstances, that is:

• 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
• in a perpendicular direction of force
• under standard ambient temperature

Impact of factors on magnetic holding capacity in practice

Practical lifting force is dependent on elements, listed from the most critical to the less significant:

• 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.

* Lifting capacity was measured by applying a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate reduces the load capacity.