SM 32x425 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

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

• Their magnetic field is durable, and after approximately ten years it drops only by ~1% (theoretically),
• They possess excellent resistance to magnetism drop as a result of opposing magnetic fields,
• A magnet with a smooth nickel surface is more attractive,
• They feature high magnetic induction at the operating surface, which increases their power,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Due to the ability of flexible molding and customization to individualized requirements, NdFeB magnets can be modeled in a variety of shapes and sizes, which increases their versatility,
• Versatile presence in modern technologies – they find application in hard drives, electromotive mechanisms, precision medical tools, as well as modern systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in miniature devices

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. 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 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 extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Due to limitations in creating nuts and complex shapes in magnets, we propose using casing - magnetic holder.
• Health risk related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the context of child health protection. It is also worth noting that small components of these magnets can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what affects it?

The load parameter shown represents the peak performance, recorded under laboratory conditions, meaning:

• on a plate made of structural steel, effectively closing the magnetic flux
• whose transverse dimension equals approx. 10 mm
• with an polished touching surface
• without the slightest insulating layer between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at conditions approx. 20°C

Lifting capacity in real conditions – factors

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

• Space between magnet and steel – every millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
• Steel type – mild steel gives the best results. Alloy admixtures lower magnetic permeability and holding force.
• Smoothness – full contact is possible only on polished steel. Rough texture reduce the real contact area, reducing force.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity was determined with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, 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 lowers the lifting capacity.