MP 5x1.5x3 / N38 - ring magnet

Pros as well as cons of neodymium magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (according to literature),
• Neodymium magnets are extremely resistant to magnetic field loss caused by magnetic disturbances,
• In other words, due to the reflective surface of nickel, the element becomes visually attractive,
• Magnets possess extremely high magnetic induction on the surface,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• In view of the ability of free molding and customization to specialized needs, NdFeB magnets can be created in a broad palette of geometric configurations, which expands the range of possible applications,
• Huge importance in advanced technology sectors – they find application in HDD drives, electromotive mechanisms, advanced medical instruments, also technologically advanced constructions.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• At strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing threads and complicated shapes in magnets, we propose using cover - magnetic mechanism.
• Potential hazard resulting from small fragments of magnets are risky, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these devices can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The load parameter shown represents the maximum value, obtained under optimal environment, specifically:

• using a base made of low-carbon steel, functioning as a circuit closing element
• with a thickness minimum 10 mm
• with an ground touching surface
• with zero gap (no impurities)
• for force acting at a right angle (in the magnet axis)
• at room temperature

What influences lifting capacity in practice

In real-world applications, the real power depends on a number of factors, ranked from the most important:

• Distance – the presence of any layer (paint, tape, gap) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Base smoothness – the more even the surface, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.