SM 32x250 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (in testing),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• By covering with a decorative coating of nickel, the element acquires an elegant look,
• Magnetic induction on the surface of the magnet remains 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...
• Thanks to modularity in designing and the capacity to adapt to individual projects,
• Huge importance in innovative solutions – they are commonly used in data components, motor assemblies, diagnostic systems, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which enables their usage in small systems

What to avoid - cons of neodymium magnets and ways of using them

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• 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
• We suggest a housing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small components of these magnets are able to be problematic in diagnostics medical when they are in the body.
• Due to neodymium price, their price is relatively high,

Highest magnetic holding force – what affects it?

Magnet power is the result of a measurement for optimal configuration, taking into account:

• on a plate made of structural steel, optimally conducting the magnetic field
• whose transverse dimension reaches at least 10 mm
• with a plane perfectly flat
• under conditions of no distance (surface-to-surface)
• for force applied at a right angle (pull-off, not shear)
• in neutral thermal conditions

Lifting capacity in practice – influencing factors

In practice, the actual holding force is determined by several key aspects, ranked from most significant:

• Gap (between the magnet and the metal), since even a very small distance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Direction of force – maximum parameter is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Chemical composition of the base – mild steel attracts best. Alloy steels lower magnetic properties and holding force.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the holding force.