UI 33x13x4 [C311] / N38 - badge holder

Pros and cons of neodymium magnets.

Besides their immense magnetic power, neodymium magnets offer the following advantages:

• They do not lose magnetism, even after nearly ten years – the drop in strength is only ~1% (based on measurements),
• Magnets very well resist against demagnetization caused by ambient magnetic noise,
• The use of an refined finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• The surface of neodymium magnets generates a concentrated magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Considering the potential of accurate forming and adaptation to specialized requirements, magnetic components can be created in a variety of shapes and sizes, which makes them more universal,
• Significant place in modern industrial fields – they are commonly used in magnetic memories, brushless drives, diagnostic systems, also industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Problematic aspects of neodymium magnets and proposals for their use:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of creating nuts in the magnet and complex forms - preferred is casing - mounting mechanism.
• Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small components of these products can disrupt the diagnostic process medical in case of swallowing.
• With mass production the cost of neodymium magnets can be a barrier,

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

The specified lifting capacity concerns the peak performance, recorded under optimal environment, namely:

• on a base made of mild steel, optimally conducting the magnetic field
• whose transverse dimension is min. 10 mm
• with an polished contact surface
• under conditions of gap-free contact (metal-to-metal)
• during detachment in a direction vertical to the plane
• at room temperature

Lifting capacity in practice – influencing factors

In practice, the actual holding force depends on several key aspects, listed from crucial:

• Clearance – existence of any layer (rust, tape, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
• Steel type – mild steel gives the best results. Higher carbon content reduce magnetic properties and lifting capacity.
• Smoothness – ideal contact is possible only on polished steel. Rough texture reduce the real contact area, reducing force.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was determined using a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, however under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.