SM 25x125 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

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

• They retain attractive force for around 10 years – the loss is just ~1% (in theory),
• They do not lose their magnetic properties even under external field action,
• By applying a shiny coating of gold, the element presents an elegant look,
• Neodymium magnets deliver maximum magnetic induction on a their surface, which ensures high operational effectiveness,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• Possibility of exact modeling and optimizing to complex conditions,
• Key role in high-tech industry – they are commonly used in computer drives, electric motors, medical devices, as well as complex engineering applications.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets and proposals for their use:

• At strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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 extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in producing threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. It is also worth noting that tiny parts of these magnets are able to be problematic in diagnostics medical when they are in the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Maximum holding power of the magnet – what affects it?

The force parameter is a theoretical maximum value executed under specific, ideal conditions:

• on a block made of structural steel, perfectly concentrating the magnetic field
• with a thickness no less than 10 mm
• with a surface perfectly flat
• without the slightest insulating layer between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at standard ambient temperature

Practical lifting capacity: influencing factors

In practice, the real power is determined by several key aspects, ranked from the most important:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Metal type – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal factor – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a slight gap {between} the magnet and the plate reduces the lifting capacity.