SM 32x225 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of rare earth magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• They have constant strength, and over nearly 10 years their performance decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under external field action,
• A magnet with a smooth nickel surface is more attractive,
• Magnetic induction on the surface of the magnet is impressive,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of exact creating and adjusting to precise applications,
• Fundamental importance in innovative solutions – they are utilized in data components, drive modules, medical devices, as well as technologically advanced constructions.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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 stable to moisture, in case of application outdoors
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using a housing - magnetic mount.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these products can disrupt the diagnostic process medical when they are in the body.
• Due to expensive raw materials, their price is higher than average,

Magnetic strength at its maximum – what affects it?

Magnet power was defined for ideal contact conditions, taking into account:

• on a base made of structural steel, optimally conducting the magnetic flux
• with a cross-section minimum 10 mm
• characterized by smoothness
• without any clearance between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

Bear in mind that the magnet holding will differ influenced by elements below, in order of importance:

• Gap between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Direction of force – highest force is obtained only during perpendicular pulling. The shear force of the magnet along the plate is usually several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin sheet does not close the flux, causing part of the power to be wasted into the air.
• Steel grade – ideal substrate is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Plate texture – ground elements ensure maximum contact, which improves field saturation. Rough surfaces weaken the grip.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as 75%. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.