SM 25x125 [2xM8] / N52 - magnetic separator

Pros as well as cons of rare earth magnets.

Apart from their superior holding force, neodymium magnets have these key benefits:

• Their magnetic field is maintained, and after approximately 10 years it decreases only by ~1% (according to research),
• They have excellent resistance to magnetic field loss as a result of external fields,
• By using a lustrous layer of nickel, the element has an modern look,
• Neodymium magnets generate maximum magnetic induction on a their surface, which allows for strong attraction,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of individual modeling and adjusting to atypical applications,
• Key role in innovative solutions – they are utilized in data components, drive modules, advanced medical instruments, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which allows their use in miniature devices

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• Limited ability of producing threads in the magnet and complicated shapes - recommended is casing - magnetic holder.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small components of these products can complicate diagnosis medical in case of swallowing.
• With large orders the cost of neodymium magnets is a challenge,

Detachment force of the magnet in optimal conditions – what affects it?

The force parameter is a measurement result performed under specific, ideal conditions:

• on a plate made of mild steel, optimally conducting the magnetic flux
• with a cross-section of at least 10 mm
• with a plane cleaned and smooth
• under conditions of ideal adhesion (metal-to-metal)
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Impact of factors on magnetic holding capacity in practice

Real force impacted by working environment parameters, including (from priority):

• Clearance – existence of foreign body (paint, tape, air) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content lower magnetic properties and holding force.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Temperature – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.

* Lifting capacity was measured by applying a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.