SM 32x250 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets.

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

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
• Neodymium magnets are remarkably resistant to loss of magnetic properties caused by external interference,
• A magnet with a metallic gold surface is more attractive,
• Neodymium magnets generate maximum magnetic induction on a small surface, which increases force concentration,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Thanks to versatility in forming and the ability to customize to individual projects,
• Universal use in modern technologies – they are utilized in magnetic memories, drive modules, medical equipment, also industrial machines.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape as well as 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
• They oxidize in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We suggest cover - magnetic mount, due to difficulties in creating threads inside the magnet and complicated forms.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. Additionally, small elements of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting force for a neodymium magnet – what it depends on?

The load parameter shown concerns the limit force, measured under laboratory conditions, specifically:

• on a base made of structural steel, effectively closing the magnetic field
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• with a plane free of scratches
• without any clearance between the magnet and steel
• under axial force direction (90-degree angle)
• at standard ambient temperature

Lifting capacity in real conditions – factors

Real force impacted by specific conditions, including (from most important):

• Air gap (betwixt the magnet and the metal), as even a tiny distance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to paint, rust or debris).
• Angle of force application – highest force is available only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – ideal substrate is pure iron steel. Cast iron may have worse magnetic properties.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the holding force.