SM 32x500 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (according to theory),
• Neodymium magnets are distinguished by exceptionally resistant to demagnetization caused by external field sources,
• By using a decorative layer of silver, the element acquires an modern look,
• Neodymium magnets create maximum magnetic induction on a contact point, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures approaching 230°C and above...
• Thanks to modularity in constructing and the ability to modify to individual projects,
• Huge importance in modern industrial fields – they are used in HDD drives, motor assemblies, precision medical tools, and other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and proposals for their use:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of making nuts in the magnet and complicated forms - preferred is casing - magnet mounting.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. Additionally, small components of these devices are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

Information about lifting capacity was defined for optimal configuration, assuming:

• on a plate made of mild steel, optimally conducting the magnetic flux
• whose thickness equals approx. 10 mm
• with an polished contact surface
• without the slightest insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at conditions approx. 20°C

Lifting capacity in practice – influencing factors

Holding efficiency impacted by working environment parameters, including (from most important):

• Distance – the presence of any layer (rust, tape, gap) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Direction of force – highest force is obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material composition – different alloys reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface finish – ideal contact is obtained only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Temperature – heating the magnet results in weakening of force. Check the maximum operating temperature for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.