SM 32x225 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

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

• They do not lose power, even after around ten years – the reduction in strength is only ~1% (according to tests),
• They show high resistance to demagnetization induced by external field influence,
• The use of an aesthetic finish of noble metals (nickel, gold, silver) causes the element to look better,
• Magnets are characterized by extremely high magnetic induction on the working surface,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures reaching 230°C and above...
• Thanks to freedom in forming and the capacity to adapt to unusual requirements,
• Universal use in electronics industry – they are used in hard drives, drive modules, advanced medical instruments, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which allows their use in compact constructions

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also raises their 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 usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Due to limitations in producing threads and complex shapes in magnets, we recommend using cover - magnetic mount.
• Health risk resulting from small fragments of magnets are risky, if swallowed, which gains importance in the context of child health protection. It is also worth noting that small elements of these devices are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what contributes to it?

Holding force of 0 kg is a measurement result conducted under standard conditions:

• with the contact of a yoke made of low-carbon steel, guaranteeing maximum field concentration
• with a thickness minimum 10 mm
• with a surface cleaned and smooth
• with zero gap (no coatings)
• for force applied at a right angle (pull-off, not shear)
• at room temperature

Impact of factors on magnetic holding capacity in practice

Holding efficiency impacted by specific conditions, including (from most important):

• Clearance – the presence of foreign body (paint, dirt, air) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Material composition – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – high temperature weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was assessed using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet and the plate decreases the lifting capacity.