SMZR 25x225 / N52 - magnetic separator with handle

Advantages and disadvantages of rare earth magnets.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• Their power is durable, and after around 10 years it decreases only by ~1% (theoretically),
• Neodymium magnets prove to be exceptionally resistant to magnetic field loss caused by external magnetic fields,
• By applying a reflective coating of gold, the element presents an elegant look,
• They are known for high magnetic induction at the operating surface, which increases their power,
• 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 potential of free shaping and adaptation to individualized needs, magnetic components can be created in a wide range of geometric configurations, which increases their versatility,
• Significant place in future technologies – they serve a role in computer drives, drive modules, medical equipment, as well as modern systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose their power 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 durability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Limited possibility of creating nuts in the magnet and complicated shapes - recommended is cover - magnetic holder.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Furthermore, small components of these devices can complicate diagnosis medical when they are in the body.
• Due to complex production process, their price is relatively high,

Detachment force of the magnet in optimal conditions – what it depends on?

Information about lifting capacity is the result of a measurement for optimal configuration, taking into account:

• on a block made of structural steel, effectively closing the magnetic field
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with a surface free of scratches
• without any insulating layer between the magnet and steel
• under axial force direction (90-degree angle)
• in stable room temperature

Key elements affecting lifting force

It is worth knowing that the working load may be lower subject to the following factors, in order of importance:

• Clearance – the presence of foreign body (paint, tape, air) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Chemical composition of the base – low-carbon steel attracts best. Alloy admixtures lower magnetic permeability and lifting capacity.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the holding force.