SMZR 32x225 / N52 - magnetic separator with handle

Strengths as well as weaknesses of NdFeB magnets.

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

• They do not lose power, even during around 10 years – the drop in lifting capacity is only ~1% (theoretically),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• Thanks to the reflective finish, the plating of nickel, gold-plated, or silver-plated gives an clean appearance,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures reaching 230°C and above...
• Possibility of accurate modeling and adapting to defined conditions,
• Versatile presence in electronics industry – they are commonly used in magnetic memories, electric drive systems, precision medical tools, as well as multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which makes them useful in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using casing - magnetic mechanism.
• Potential hazard to health – tiny shards of magnets pose a threat, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, tiny parts of these products can disrupt the diagnostic process medical when they are in the body.
• Due to complex production process, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what affects it?

The specified lifting capacity refers to the limit force, measured under laboratory conditions, specifically:

• with the use of a yoke made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of at least 10 mm to avoid saturation
• with a surface cleaned and smooth
• under conditions of gap-free contact (surface-to-surface)
• during detachment in a direction perpendicular to the mounting surface
• at standard ambient temperature

What influences lifting capacity in practice

Please note that the magnet holding will differ subject to elements below, starting with the most relevant:

• Air gap (betwixt the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to paint, rust or dirt).
• Direction of force – highest force is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is typically many times smaller (approx. 1/5 of the lifting capacity).
• Metal 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 high-permeability steel. Stainless steels may have worse magnetic properties.
• Surface structure – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.