SM 25x200 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They do not lose strength, even after around ten years – the decrease in power is only ~1% (according to tests),
• Neodymium magnets remain exceptionally resistant to loss of magnetic properties caused by external magnetic fields,
• In other words, due to the aesthetic surface of gold, the element gains visual value,
• Magnets are characterized by extremely high magnetic induction on the outer layer,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to build),
• In view of the ability of free molding and adaptation to individualized solutions, neodymium magnets can be modeled in a broad palette of forms and dimensions, which amplifies use scope,
• Key role in high-tech industry – they are used in hard drives, electric motors, diagnostic systems, as well as multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding 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 as well as corrosion.
• Due to limitations in producing nuts and complicated shapes in magnets, we propose using casing - magnetic mount.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the context of child health protection. Furthermore, small components of these products are able to disrupt the diagnostic process medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Maximum holding power of the magnet – what affects it?

Magnet power was determined for optimal configuration, assuming:

• with the use of a sheet made of special test steel, ensuring maximum field concentration
• possessing a massiveness of at least 10 mm to ensure full flux closure
• characterized by smoothness
• under conditions of gap-free contact (surface-to-surface)
• during pulling in a direction vertical to the mounting surface
• in temp. approx. 20°C

Practical aspects of lifting capacity – factors

Real force is affected by working environment parameters, such as (from priority):

• Air gap (between the magnet and the plate), because even a tiny clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Direction of force – maximum parameter is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures lower magnetic permeability and lifting capacity.
• Surface finish – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.