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

Strengths and weaknesses of rare earth magnets.

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

• They retain magnetic properties for almost 10 years – the drop is just ~1% (based on simulations),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• Thanks to the shimmering finish, the coating of Ni-Cu-Ni, gold, or silver-plated gives an elegant appearance,
• Magnetic induction on the top side of the magnet turns out to be maximum,
• 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 constructing and the capacity to adapt to individual projects,
• Key role in high-tech industry – they are used in mass storage devices, drive modules, advanced medical instruments, as well as multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We suggest cover - magnetic mount, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these devices are able to complicate diagnosis medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what affects it?

The load parameter shown represents the maximum value, obtained under ideal test conditions, meaning:

• with the use of a yoke made of special test steel, ensuring maximum field concentration
• with a cross-section minimum 10 mm
• with an ideally smooth touching surface
• with zero gap (no coatings)
• under vertical application of breakaway force (90-degree angle)
• at standard ambient temperature

Magnet lifting force in use – key factors

Real force is influenced by specific conditions, including (from priority):

• Gap (between the magnet and the plate), since even a microscopic clearance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Loading method – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Smoothness – ideal contact is obtained only on polished steel. Rough texture create air cushions, reducing force.
• Temperature – temperature increase results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.