ZM XMAG2 210 elementów - magnetic toy

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their notable magnetism, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They show exceptional resistance to demagnetization from outside magnetic sources,
• Thanks to the shiny finish and silver coating, they have an aesthetic appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• 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),
• With the option for customized forming and precise design, these magnets can be produced in multiple shapes and sizes, greatly improving application potential,
• Key role in cutting-edge sectors – they are utilized in computer drives, electric drives, medical equipment or even technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in small systems

Disadvantages of neodymium magnets:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to external force, they should be placed in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and enhances its overall resistance,
• 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 moisture can degrade. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• Limited ability to create complex details in the magnet – the use of a mechanical support is recommended,
• Safety concern related to magnet particles may arise, in case of ingestion, which is important in the protection of children. Additionally, miniature parts from these assemblies can hinder health screening if inside the body,
• In cases of large-volume purchasing, neodymium magnet cost is a challenge,

Magnetic strength at its maximum – what affects it?

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

• with the use of low-carbon steel plate acting as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a polished side
• with no separation
• with vertical force applied
• at room temperature

Key elements affecting lifting force

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

• Air gap between the magnet and the plate, because 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 testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, however under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.