ZM XMAG2 105 elementów - magnetic toy

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is maintained, and after approximately ten years, it drops only by ~1% (according to research),
• They show strong resistance to demagnetization from outside magnetic sources,
• Because of the lustrous layer of silver, the component looks visually appealing,
• They have extremely strong magnetic induction on the surface of the magnet,
• 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),
• The ability for custom shaping or customization to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which amplifies their functionality across industries,
• Key role in cutting-edge sectors – they are used in HDDs, electric motors, medical equipment and sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in small dimensions, which makes them ideal in compact constructions

Disadvantages of NdFeB magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to mechanical hits, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage while also enhances its overall strength,
• High temperatures may significantly reduce the strength 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 wet conditions can degrade. Therefore, for outdoor applications, it's best to use waterproof types made of coated materials,
• Limited ability to create complex details in the magnet – the use of a housing is recommended,
• Health risk from tiny pieces may arise, especially if swallowed, which is significant in the protection of children. Moreover, tiny components from these assemblies might interfere with diagnostics once in the system,
• In cases of mass production, neodymium magnet cost may be a barrier,

Breakaway strength of the magnet in ideal conditions – what it depends on?

The given pulling force of the magnet represents the maximum force, measured in ideal conditions, that is:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with zero air gap
• under perpendicular detachment force
• at room temperature

Impact of factors on magnetic holding capacity in practice

In practice, the holding capacity of a magnet is conditioned by the following aspects, in descending order of importance:

• Air gap between the magnet and the plate, as 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 determined using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.