ZK XLINK 1026 elementów - construction toy

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They retain their magnetic properties for around ten years – the drop is just ~1% (according to analyses),
• They show strong resistance to demagnetization from external field exposure,
• The use of a polished gold surface provides a smooth finish,
• The outer field strength of the magnet shows remarkable magnetic properties,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to build),
• The ability for precise shaping or adaptation to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
• Key role in advanced technical fields – they are utilized in computer drives, electric drives, clinical machines as well as other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in small dimensions, which makes them ideal in miniature devices

Disadvantages of NdFeB magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture and enhances its overall durability,
• High temperatures may significantly reduce the magnetic power 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 humidity can rust. Therefore, for outdoor applications, it's best to use waterproof types made of coated materials,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is restricted,
• Health risk due to small fragments may arise, especially if swallowed, which is significant in the family environments. It should also be noted that minuscule fragments from these devices might complicate medical imaging after being swallowed,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum magnetic pulling force – what contributes to it?

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

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a refined outer layer
• in conditions of no clearance
• with vertical force applied
• in normal thermal conditions

Determinants of lifting force in real conditions

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, 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 testing was conducted on a smooth plate of suitable thickness, under perpendicular forces, in contrast under parallel forces the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.