SM 32x300 [2xM8] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

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

• They do not lose magnetism, even during around ten years – the decrease in power is only ~1% (based on measurements),
• Magnets perfectly protect themselves against demagnetization caused by foreign field sources,
• Thanks to the glossy finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an clean appearance,
• They show high magnetic induction at the operating surface, which increases their power,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of precise creating and optimizing to defined needs,
• Significant place in innovative solutions – they are commonly used in HDD drives, motor assemblies, medical equipment, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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 advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Limited ability of producing nuts in the magnet and complex forms - recommended is casing - magnet mounting.
• Possible danger related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Additionally, small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
• With large orders the cost of neodymium magnets is a challenge,

Highest magnetic holding force – what affects it?

The lifting capacity listed is a theoretical maximum value conducted under specific, ideal conditions:

• on a base made of structural steel, optimally conducting the magnetic field
• whose thickness is min. 10 mm
• characterized by lack of roughness
• under conditions of ideal adhesion (surface-to-surface)
• for force applied at a right angle (pull-off, not shear)
• in neutral thermal conditions

Magnet lifting force in use – key factors

In practice, the actual lifting capacity depends on many variables, presented from most significant:

• Distance – existence of foreign body (rust, tape, air) interrupts the magnetic circuit, which reduces power rapidly (even by 50% at 0.5 mm).
• Load vector – maximum parameter is reached only during perpendicular pulling. The force required to slide of the magnet along the surface is usually several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Material type – ideal substrate is pure iron steel. Stainless steels may attract less.
• Smoothness – ideal contact is possible only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.