SM 25x350 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

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

• They do not lose magnetism, even after nearly 10 years – the drop in strength is only ~1% (based on measurements),
• Magnets perfectly resist against demagnetization caused by foreign field sources,
• Thanks to the elegant finish, the coating of Ni-Cu-Ni, gold-plated, or silver-plated gives an visually attractive appearance,
• Magnets exhibit maximum magnetic induction on the surface,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures approaching 230°C and above...
• Possibility of detailed shaping as well as optimizing to precise conditions,
• Versatile presence in future technologies – they are commonly used in data components, motor assemblies, medical equipment, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which allows their use in miniature devices

Problematic aspects of neodymium magnets: tips and applications.

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only secures them against impacts but also increases their durability
• We warn that neodymium magnets can reduce 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 prevent oxidation and corrosion.
• Limited ability of creating nuts in the magnet and complex forms - recommended is cover - magnet mounting.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Furthermore, small elements of these products can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum lifting force for a neodymium magnet – what it depends on?

Holding force of 0 kg is a result of laboratory testing executed under standard conditions:

• using a sheet made of mild steel, acting as a ideal flux conductor
• with a cross-section no less than 10 mm
• with an polished touching surface
• without the slightest insulating layer between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at room temperature

Magnet lifting force in use – key factors

Holding efficiency is affected by specific conditions, including (from most important):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Chemical composition of the base – mild steel attracts best. Alloy admixtures lower magnetic permeability and holding force.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate decreases the lifting capacity.