SMZR 25x200 / N52 - magnetic separator with handle

Pros and cons of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They do not lose strength, even during nearly ten years – the drop in lifting capacity is only ~1% (based on measurements),
• They are resistant to demagnetization induced by presence of other magnetic fields,
• By covering with a lustrous coating of silver, the element has an proper look,
• The surface of neodymium magnets generates a unique magnetic field – this is a distinguishing feature,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• Possibility of detailed creating as well as modifying to atypical requirements,
• Significant place in modern technologies – they find application in hard drives, electromotive mechanisms, precision medical tools, and industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend a housing - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated forms.
• Potential hazard related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the context of child health protection. Additionally, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets can be a barrier,

Magnetic strength at its maximum – what contributes to it?

Information about lifting capacity was determined for optimal configuration, including:

• with the application of a yoke made of low-carbon steel, ensuring full magnetic saturation
• possessing a massiveness of min. 10 mm to ensure full flux closure
• with an ideally smooth contact surface
• without any air gap between the magnet and steel
• under axial force direction (90-degree angle)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

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

• Air gap (betwixt the magnet and the metal), since even a very small distance (e.g. 0.5 mm) can cause a reduction in force by up to 50% (this also applies to varnish, rust or debris).
• Load vector – maximum parameter is available only during pulling at a 90° angle. The shear force of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin sheet does not accept the full field, causing part of the flux to be escaped into the air.
• Material type – ideal substrate is high-permeability steel. Hardened steels may attract less.
• Surface condition – ground elements ensure maximum contact, which increases field saturation. Uneven metal weaken the grip.
• Thermal environment – temperature increase 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, whereas under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet and the plate reduces the load capacity.