SM 18x100 [2xM5] / N42 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• They do not lose their magnetic properties even under close interference source,
• By using a decorative layer of gold, the element presents an aesthetic look,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• In view of the ability of flexible forming and adaptation to specialized requirements, neodymium magnets can be manufactured in a wide range of shapes and sizes, which amplifies use scope,
• Key role in electronics industry – they serve a role in magnetic memories, motor assemblies, medical devices, and modern systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Drawbacks and weaknesses of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited possibility of making nuts in the magnet and complicated forms - preferred is cover - magnet mounting.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, tiny parts of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• With mass production the cost of neodymium magnets is a challenge,

Maximum lifting capacity of the magnet – what affects it?

Magnet power is the result of a measurement for optimal configuration, including:

• on a block made of structural steel, effectively closing the magnetic flux
• possessing a massiveness of at least 10 mm to avoid saturation
• characterized by lack of roughness
• without any air gap between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

During everyday use, the real power results from a number of factors, presented from crucial:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – highest force is reached only during perpendicular pulling. The force required to slide of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin plate does not accept the full field, causing part of the power to be escaped to the other side.
• Metal type – not every steel reacts the same. Alloy additives worsen the interaction with the magnet.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Thermal environment – temperature increase causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.