MW 5x25 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their superior power, neodymium magnets have these key benefits:

• They have constant strength, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• Their ability to resist magnetic interference from external fields is notable,
• The use of a mirror-like silver surface provides a smooth finish,
• The outer field strength of the magnet shows elevated magnetic properties,
• 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 geometry),
• With the option for customized forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Significant impact in advanced technical fields – they are utilized in computer drives, rotating machines, clinical machines along with other advanced devices,
• 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 sudden impact. If the magnets are exposed to external force, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time reinforces its overall strength,
• They lose power at elevated temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to wet conditions can corrode. Therefore, for outdoor applications, we suggest waterproof types made of non-metallic composites,
• Limited ability to create threads in the magnet – the use of a housing is recommended,
• Potential hazard linked to microscopic shards may arise, if ingested accidentally, which is notable in the context of child safety. Furthermore, tiny components from these devices may interfere with diagnostics when ingested,
• In cases of large-volume purchasing, neodymium magnet cost may be a barrier,

Maximum lifting force for a neodymium magnet – what affects it?

The given holding capacity of the magnet corresponds to the highest holding force, assessed in the best circumstances, 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 no separation
• under perpendicular detachment force
• under standard ambient temperature

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes 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 using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate lowers the lifting capacity.