SM 25x100 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

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

• They retain full power for nearly 10 years – the drop is just ~1% (according to analyses),
• Neodymium magnets remain remarkably resistant to loss of magnetic properties caused by magnetic disturbances,
• Thanks to the elegant finish, the coating of nickel, gold-plated, or silver-plated gives an elegant appearance,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Possibility of individual shaping as well as adjusting to specific needs,
• Huge importance in innovative solutions – they are utilized in HDD drives, brushless drives, diagnostic systems, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which allows their use in small systems

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and 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
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• We recommend casing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex forms.
• Potential hazard to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these products are able to complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price is higher than average,

Maximum lifting force for a neodymium magnet – what affects it?

Magnet power was determined for optimal configuration, including:

• with the application of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• whose transverse dimension equals approx. 10 mm
• characterized by even structure
• without any insulating layer between the magnet and steel
• under axial force vector (90-degree angle)
• in temp. approx. 20°C

What influences lifting capacity in practice

It is worth knowing that the application force will differ subject to elements below, starting with the most relevant:

• Distance – existence of foreign body (rust, tape, air) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin sheet causes magnetic saturation, causing part of the power to be escaped into the air.
• Steel grade – the best choice is high-permeability steel. Hardened steels may attract less.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, however under shearing force the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate lowers the load capacity.