SMZR 25x225 / N52 - magnetic separator with handle

Advantages as well as disadvantages of NdFeB magnets.

Besides their immense strength, neodymium magnets offer the following advantages:

• Their power remains stable, and after around ten years it drops only by ~1% (theoretically),
• They possess excellent resistance to magnetic field loss when exposed to external fields,
• A magnet with a metallic silver surface looks better,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to versatility in shaping and the capacity to adapt to client solutions,
• Fundamental importance in electronics industry – they are commonly used in HDD drives, electric drive systems, advanced medical instruments, also industrial machines.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

What to avoid - cons of neodymium magnets and proposals for their use:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only secures them against impacts but also raises their durability
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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 very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is a housing - magnet mounting.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small components of these products can disrupt the diagnostic process medical in case of swallowing.
• Due to complex production process, their price is relatively high,

Maximum lifting capacity of the magnet – what contributes to it?

The lifting capacity listed is a theoretical maximum value performed under specific, ideal conditions:

• on a block made of mild steel, perfectly concentrating the magnetic field
• with a cross-section minimum 10 mm
• with a plane free of scratches
• with zero gap (without coatings)
• during pulling in a direction perpendicular to the plane
• at standard ambient temperature

Lifting capacity in real conditions – factors

Please note that the application force will differ depending on the following factors, starting with the most relevant:

• Gap between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Steel thickness – too thin steel causes magnetic saturation, causing part of the flux to be lost to the other side.
• Plate material – mild steel attracts best. Alloy admixtures reduce magnetic permeability and lifting capacity.
• Surface quality – the smoother and more polished the surface, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Temperature – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.