SM 25x275 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of rare earth magnets.

Besides their immense magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They are extremely resistant to demagnetization induced by external disturbances,
• Thanks to the glossy finish, the coating of nickel, gold-plated, or silver-plated gives an modern appearance,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to the ability of free shaping and customization to unique requirements, magnetic components can be created in a broad palette of shapes and sizes, which expands the range of possible applications,
• Significant place in advanced technology sectors – they are utilized in mass storage devices, electric motors, diagnostic systems, and industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: application proposals

• At strong impacts they can break, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 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.
• We suggest a housing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complicated shapes.
• Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the context of child safety. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical after entering the body.
• With mass production the cost of neodymium magnets can be a barrier,

Best holding force of the magnet in ideal parameters – what it depends on?

Holding force of 0 kg is a measurement result executed under the following configuration:

• on a base made of structural steel, perfectly concentrating the magnetic field
• possessing a massiveness of min. 10 mm to ensure full flux closure
• characterized by smoothness
• without any insulating layer between the magnet and steel
• under perpendicular force vector (90-degree angle)
• in stable room temperature

Practical aspects of lifting capacity – factors

Please note that the application force may be lower influenced by the following factors, in order of importance:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• 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 surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Steel thickness – too thin steel does not accept the full field, causing part of the flux to be escaped to the other side.
• Plate material – low-carbon steel gives the best results. Alloy steels lower magnetic properties and holding force.
• Plate texture – smooth surfaces guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate reduces the lifting capacity.