SM 32x125 [2xM8] / N52 - magnetic separator

Pros as well as cons of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain full power for almost 10 years – the drop is just ~1% (in theory),
• They possess excellent resistance to weakening of magnetic properties due to opposing magnetic fields,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to look better,
• Magnets have exceptionally strong magnetic induction on the surface,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Possibility of precise shaping as well as modifying to atypical conditions,
• Fundamental importance in future technologies – they are commonly used in magnetic memories, electric drive systems, precision medical tools, and modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• 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 decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 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, in case of application outdoors
• Due to limitations in creating threads and complicated forms in magnets, we propose using casing - magnetic holder.
• Health risk related to microscopic parts of magnets are risky, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these magnets can disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Highest magnetic holding force – what affects it?

The force parameter is a theoretical maximum value executed under the following configuration:

• using a sheet made of high-permeability steel, functioning as a magnetic yoke
• with a cross-section minimum 10 mm
• characterized by smoothness
• without any air gap between the magnet and steel
• during detachment in a direction vertical to the plane
• at room temperature

Determinants of practical lifting force of a magnet

During everyday use, the real power depends on several key aspects, presented from crucial:

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material type – ideal substrate is high-permeability steel. Cast iron may generate lower lifting capacity.
• Smoothness – full contact is obtained only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate lowers the lifting capacity.