SMZR 32x125 / N52 - magnetic separator with handle

Strengths and weaknesses of NdFeB magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They do not lose magnetism, even over around 10 years – the decrease in strength is only ~1% (theoretically),
• They feature excellent resistance to magnetism drop when exposed to external magnetic sources,
• By covering with a reflective coating of gold, the element acquires an aesthetic look,
• Magnets have extremely high magnetic induction on the outer layer,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Considering the option of accurate forming and adaptation to specialized projects, magnetic components can be modeled in a broad palette of shapes and sizes, which amplifies use scope,
• Key role in modern industrial fields – they are commonly used in data components, drive modules, diagnostic systems, as well as other advanced devices.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding 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
• Limited ability of producing threads in the magnet and complicated shapes - recommended is cover - magnet mounting.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which gains importance in the context of child health protection. Furthermore, tiny parts of these products can be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The lifting capacity listed is a measurement result executed under standard conditions:

• on a block made of mild steel, optimally conducting the magnetic field
• whose thickness equals approx. 10 mm
• with an polished contact surface
• without the slightest clearance between the magnet and steel
• under perpendicular force direction (90-degree angle)
• at temperature room level

Key elements affecting lifting force

In practice, the actual lifting capacity depends on many variables, listed from crucial:

• Gap between magnet and steel – every millimeter of separation (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – mild steel gives the best results. Alloy steels reduce magnetic permeability and lifting capacity.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Operating temperature – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.