SMZR 25x200 / N52 - magnetic separator with handle

Advantages and disadvantages of NdFeB magnets.

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

• Their strength is durable, and after approximately 10 years it drops only by ~1% (theoretically),
• They show high resistance to demagnetization induced by external field influence,
• A magnet with a metallic nickel surface has better aesthetics,
• They are known for high magnetic induction at the operating surface, which increases their power,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Possibility of exact shaping and adjusting to complex needs,
• Universal use in innovative solutions – they are used in hard drives, electric drive systems, 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:

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its 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 magnets in rubber or plastics, which secure oxidation and corrosion.
• We recommend a housing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complex shapes.
• Potential hazard to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. It is also worth noting that small components of these products can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

Holding force of 0 kg is a result of laboratory testing executed under the following configuration:

• using a plate made of mild steel, serving as a magnetic yoke
• with a cross-section of at least 10 mm
• characterized by even structure
• with direct contact (no coatings)
• under axial force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

Effective lifting capacity impacted by working environment parameters, such as (from priority):

• Air gap (betwixt the magnet and the metal), as even a microscopic clearance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of converting into lifting capacity.
• Steel type – low-carbon steel attracts best. Higher carbon content lower magnetic permeability and lifting capacity.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture create air cushions, reducing force.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.