SM 32x200 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

Apart from their strong magnetism, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• They are noted for resistance to demagnetization induced by external disturbances,
• Thanks to the metallic finish, the surface of Ni-Cu-Ni, gold-plated, or silver gives an clean appearance,
• Neodymium magnets generate maximum magnetic induction on a contact point, which increases force concentration,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• In view of the possibility of accurate molding and adaptation to individualized solutions, magnetic components can be created in a variety of shapes and sizes, which makes them more universal,
• Huge importance in innovative solutions – they are utilized in HDD drives, drive modules, diagnostic systems, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in miniature devices

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 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, when using outdoors
• We suggest a housing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complicated shapes.
• Potential hazard resulting from small fragments of magnets are risky, if swallowed, which is particularly important in the context of child health protection. Furthermore, small elements of these magnets can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

Highest magnetic holding force – what contributes to it?

The force parameter is a measurement result performed under specific, ideal conditions:

• using a plate made of mild steel, acting as a circuit closing element
• whose transverse dimension equals approx. 10 mm
• characterized by smoothness
• without any air gap between the magnet and steel
• during detachment in a direction perpendicular to the plane
• at ambient temperature room level

Magnet lifting force in use – key factors

Real force is influenced by working environment parameters, including (from most important):

• Gap (betwixt the magnet and the plate), because even a very small clearance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Angle of force application – maximum parameter is reached only during perpendicular pulling. The force required to slide of the magnet along the plate is typically several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick plate does not accept the full field, causing part of the power to be escaped to the other side.
• Metal type – different alloys reacts the same. Alloy additives worsen the attraction effect.
• Surface finish – full contact is obtained only on smooth steel. Rough texture reduce the real contact area, reducing force.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity was determined by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet and the plate reduces the holding force.