SMZR 25x200 / N52 - magnetic separator with handle

Strengths as well as weaknesses of NdFeB magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They do not lose power, even over approximately 10 years – the drop in power is only ~1% (according to tests),
• Magnets effectively defend themselves against demagnetization caused by external fields,
• By covering with a lustrous coating of gold, the element presents an elegant look,
• Neodymium magnets create maximum magnetic induction on a contact point, which allows for strong attraction,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Due to the ability of flexible molding and adaptation to custom projects, magnetic components can be modeled in a broad palette of geometric configurations, which increases their versatility,
• Versatile presence in future technologies – they are commonly used in HDD drives, motor assemblies, medical devices, and technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Due to limitations in producing threads and complex shapes in magnets, we propose using a housing - magnetic mount.
• Possible danger related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the context of child health protection. Additionally, tiny parts of these products can be problematic in diagnostics medical in case of swallowing.
• With mass production the cost of neodymium magnets is a challenge,

Optimal lifting capacity of a neodymium magnet – what affects it?

The force parameter is a theoretical maximum value executed under specific, ideal conditions:

• on a base made of structural steel, effectively closing the magnetic flux
• with a cross-section minimum 10 mm
• with a surface cleaned and smooth
• without the slightest clearance between the magnet and steel
• during pulling in a direction perpendicular to the plane
• at temperature room level

Magnet lifting force in use – key factors

Please note that the application force may be lower influenced by the following factors, starting with the most relevant:

• Clearance – existence of foreign body (rust, tape, air) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin plate does not close the flux, causing part of the flux to be escaped into the air.
• Steel grade – the best choice is pure iron steel. Cast iron 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.
• Temperature influence – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, 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.