SM 25x175 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• Neodymium magnets are characterized by remarkably resistant to demagnetization caused by external field sources,
• Thanks to the elegant finish, the surface of Ni-Cu-Ni, gold, or silver-plated gives an visually attractive appearance,
• Magnets possess excellent magnetic induction on the outer layer,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of exact machining as well as optimizing to atypical requirements,
• Huge importance in modern technologies – they serve a role in computer drives, electric drive systems, diagnostic systems, also complex engineering applications.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Characteristics of disadvantages of neodymium magnets and proposals for their use:

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their strength 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 rust. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We suggest cover - magnetic mount, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the context of child safety. Furthermore, tiny parts of these magnets are able to complicate diagnosis medical after entering the body.
• Due to neodymium price, their price is higher than average,

Maximum magnetic pulling force – what affects it?

Breakaway force was defined for the most favorable conditions, taking into account:

• on a base made of structural steel, optimally conducting the magnetic field
• with a thickness no less than 10 mm
• with a surface cleaned and smooth
• without any clearance between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• in neutral thermal conditions

Practical lifting capacity: influencing factors

In practice, the actual holding force is determined by several key aspects, listed from crucial:

• Distance (between the magnet and the plate), because even a tiny distance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Angle of force application – maximum parameter is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the plate is usually many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content decrease magnetic permeability and lifting capacity.
• Surface structure – the more even the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Heat – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate reduces the holding force.