MW 8x1.5 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• They do not lose magnetism, even over nearly ten years – the drop in power is only ~1% (theoretically),
• They feature excellent resistance to magnetism drop when exposed to external fields,
• By using a smooth layer of nickel, the element gains an professional look,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures reaching 230°C and above...
• Thanks to freedom in constructing and the capacity to adapt to individual projects,
• Huge importance in future technologies – they are commonly used in hard drives, drive modules, precision medical tools, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which allows their use in compact constructions

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets lose their power 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We recommend casing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these magnets can be problematic in diagnostics medical when they are in 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 affects it?

Magnet power was determined for optimal configuration, including:

• with the contact of a sheet made of low-carbon steel, ensuring full magnetic saturation
• with a thickness no less than 10 mm
• characterized by smoothness
• under conditions of gap-free contact (surface-to-surface)
• under vertical force direction (90-degree angle)
• at ambient temperature room level

Practical aspects of lifting capacity – factors

Effective lifting capacity is influenced by working environment parameters, including (from priority):

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a minimal clearance {between} the magnet and the plate lowers the holding force.