SM 25x225 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They do not lose power, even during nearly 10 years – the reduction in lifting capacity is only ~1% (theoretically),
• Neodymium magnets are distinguished by exceptionally resistant to demagnetization caused by external field sources,
• The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to look better,
• The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures approaching 230°C and above...
• Thanks to flexibility in forming and the ability to adapt to client solutions,
• Versatile presence in future technologies – they are used in data components, brushless drives, medical equipment, and modern systems.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation as well as corrosion.
• Due to limitations in producing nuts and complicated forms in magnets, we propose using a housing - magnetic mount.
• Health risk to health – tiny shards of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Additionally, tiny parts of these products are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

Magnet power was defined for ideal contact conditions, taking into account:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• possessing a thickness of minimum 10 mm to avoid saturation
• with an polished contact surface
• with zero gap (no paint)
• for force applied at a right angle (in the magnet axis)
• at ambient temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

In practice, the real power depends on many variables, presented from crucial:

• Distance (between the magnet and the metal), because even a very small clearance (e.g. 0.5 mm) results in a reduction in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – maximum parameter is reached only during pulling at a 90° angle. The force required to slide of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material type – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Temperature influence – hot environment reduces magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet and the plate reduces the holding force.