SM 25x100 [2xM8] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

Besides their exceptional pulling force, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (according to literature),
• They have excellent resistance to magnetism drop when exposed to external magnetic sources,
• By covering with a lustrous layer of silver, the element presents an modern look,
• Neodymium magnets deliver maximum magnetic induction on a their surface, which increases force concentration,
• 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 versatility in forming and the capacity to customize to complex applications,
• Key role in innovative solutions – they serve a role in magnetic memories, electric motors, advanced medical instruments, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in small systems

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. 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 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
• We recommend casing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these magnets can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum lifting capacity of the magnet – what it depends on?

The load parameter shown refers to the limit force, recorded under optimal environment, specifically:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• with a cross-section of at least 10 mm
• with an polished contact surface
• without any air gap between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

It is worth knowing that the working load will differ influenced by the following factors, starting with the most relevant:

• Air gap (betwixt the magnet and the plate), as even a tiny clearance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Plate material – low-carbon steel gives the best results. Alloy steels lower magnetic permeability and holding force.
• Surface quality – the more even the surface, the larger the contact zone and higher the lifting capacity. Roughness creates an air distance.
• Thermal factor – high temperature reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate lowers the holding force.