UMGGW 66x8.5 [M8] GW / N38 - magnetic holder rubber internal thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their exceptional field intensity, neodymium magnets offer the following advantages:

• They do not lose their magnetism, even after approximately ten years – the loss of power is only ~1% (according to tests),
• They remain magnetized despite exposure to magnetic noise,
• Because of the brilliant layer of nickel, the component looks high-end,
• They have extremely strong 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 magnetic form),
• Thanks to the flexibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in various configurations, which broadens their functional possibilities,
• Significant impact in modern technologies – they are used in computer drives, electric motors, diagnostic apparatus along with sophisticated instruments,
• Thanks to their power density, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of neodymium magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time reinforces its overall strength,
• 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 damp air can degrade. Therefore, for outdoor applications, we recommend waterproof types made of non-metallic composites,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing fine shapes directly in the magnet,
• Health risk linked to microscopic shards may arise, when consumed by mistake, which is crucial in the health of young users. Additionally, miniature parts from these assemblies may hinder health screening once in the system,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Highest magnetic holding force – what contributes to it?

The given holding capacity of the magnet represents the highest holding force, calculated in the best circumstances, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a smooth surface
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Determinants of practical lifting force of a magnet

In practice, the holding capacity of a magnet is affected by these factors, in descending order of importance:

• 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 testing was performed on a smooth plate of suitable thickness, under perpendicular forces, whereas under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.