SMZR 25x200 / N52 - magnetic separator with handle

Pros as well as cons of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They do not lose strength, even over nearly ten years – the reduction in lifting capacity is only ~1% (according to tests),
• They do not lose their magnetic properties even under strong external field,
• The use of an refined layer of noble metals (nickel, gold, silver) causes the element to present itself better,
• The surface of neodymium magnets generates a intense magnetic field – this is a distinguishing feature,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Considering the ability of accurate molding and customization to specialized projects, NdFeB magnets can be created in a wide range of forms and dimensions, which makes them more universal,
• Fundamental importance in future technologies – they serve a role in magnetic memories, drive modules, medical equipment, and multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Cons of neodymium magnets and ways of using them

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution secures the magnet and simultaneously improves its 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 start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in producing threads and complicated shapes in magnets, we recommend using cover - magnetic mechanism.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child safety. It is also worth noting that tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is a challenge,

Magnetic strength at its maximum – what affects it?

Holding force of 0.00 kg is a measurement result conducted under specific, ideal conditions:

• using a base made of mild steel, acting as a ideal flux conductor
• possessing a thickness of minimum 10 mm to avoid saturation
• characterized by lack of roughness
• under conditions of no distance (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Impact of factors on magnetic holding capacity in practice

Real force is influenced by working environment parameters, such as (from most important):

• Distance – the presence of any layer (paint, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – too thin plate causes magnetic saturation, causing part of the flux to be escaped to the other side.
• Steel type – low-carbon steel gives the best results. Higher carbon content lower magnetic properties and lifting capacity.
• Surface finish – full contact is obtained only on polished steel. Rough texture create air cushions, reducing force.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet and the plate reduces the lifting capacity.