UMT 12x20 purple / N38 - board holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• Their ability to resist magnetic interference from external fields is notable,
• Because of the reflective layer of silver, the component looks aesthetically refined,
• They have very high magnetic induction on the surface of the magnet,
• Neodymium magnets are known for strong 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 specific requirements, neodymium magnets can be created in different geometries, which broadens their usage potential,
• Key role in cutting-edge sectors – they find application in computer drives, electromechanical systems, clinical machines or even technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to external force, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time strengthens its overall strength,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent deterioration 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,
• Magnets exposed to damp air can corrode. Therefore, for outdoor applications, we advise waterproof types made of non-metallic composites,
• Limited ability to create precision features in the magnet – the use of a external casing is recommended,
• Potential hazard linked to microscopic shards may arise, if ingested accidentally, which is significant in the context of child safety. Furthermore, miniature parts from these products can complicate medical imaging once in the system,
• In cases of large-volume purchasing, neodymium magnet cost may be a barrier,

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

The given pulling force of the magnet corresponds to the maximum force, assessed under optimal conditions, specifically:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with no separation
• under perpendicular detachment force
• at room temperature

Magnet lifting force in use – key factors

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• 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 assessed using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.