SM 25x350 [2xM8] / N52 - magnetic separator

Pros as well as cons of neodymium magnets.

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

• Their strength remains stable, and after around 10 years it drops only by ~1% (theoretically),
• They are resistant to demagnetization induced by presence of other magnetic fields,
• A magnet with a smooth gold surface has better aesthetics,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to modularity in shaping and the ability to adapt to individual projects,
• Wide application in innovative solutions – they are utilized in data components, electric motors, advanced medical instruments, and other advanced devices.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited possibility of making threads in the magnet and complicated forms - recommended is cover - mounting mechanism.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the context of child safety. Additionally, small components of these products can disrupt the diagnostic process medical in case of swallowing.
• Due to neodymium price, their price is higher than average,

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

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

• using a base made of mild steel, functioning as a circuit closing element
• possessing a thickness of min. 10 mm to avoid saturation
• with an polished contact surface
• without the slightest air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at conditions approx. 20°C

What influences lifting capacity in practice

In real-world applications, the actual lifting capacity depends on several key aspects, ranked from crucial:

• Distance – the presence of any layer (paint, tape, air) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick steel does not accept the full field, causing part of the power to be wasted into the air.
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface quality – the more even the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.