SM 25x150 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

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

• They retain attractive force for around 10 years – the drop is just ~1% (in theory),
• Magnets effectively resist against loss of magnetization caused by foreign field sources,
• In other words, due to the reflective layer of gold, the element gains visual value,
• They are known for high magnetic induction at the operating surface, making them more effective,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling operation at temperatures reaching 230°C and above...
• Possibility of custom modeling and optimizing to individual needs,
• Wide application in modern technologies – they are commonly used in mass storage devices, brushless drives, precision medical tools, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of making threads in the magnet and complex shapes - recommended is casing - magnet mounting.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, small elements of these devices are able to be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets can be a barrier,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The specified lifting capacity represents the peak performance, recorded under optimal environment, namely:

• using a base made of high-permeability steel, serving as a magnetic yoke
• with a cross-section no less than 10 mm
• with a surface cleaned and smooth
• without the slightest clearance between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• at room temperature

What influences lifting capacity in practice

Holding efficiency is affected by specific conditions, mainly (from priority):

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Direction of force – maximum parameter is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Temperature influence – hot environment weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was measured with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.