MP 5x2.7/1.2x5 C / N38 - ring magnet

Advantages as well as disadvantages of NdFeB magnets.

Apart from their notable power, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (based on calculations),
• Magnets effectively protect themselves against loss of magnetization caused by foreign field sources,
• A magnet with a shiny silver surface has an effective appearance,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for operation at temperatures reaching 230°C and above...
• Thanks to versatility in forming and the ability to modify to client solutions,
• Wide application in electronics industry – they are utilized in HDD drives, brushless drives, medical devices, as well as modern systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• Susceptibility to cracking 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 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. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing nuts and complicated shapes in magnets, we recommend using a housing - magnetic mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which gains importance in the context of child health protection. It is also worth noting that small elements of these magnets can complicate diagnosis medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Optimal lifting capacity of a neodymium magnet – what it depends on?

Information about lifting capacity is the result of a measurement for optimal configuration, assuming:

• with the use of a sheet made of low-carbon steel, ensuring maximum field concentration
• whose transverse dimension reaches at least 10 mm
• with an ideally smooth contact surface
• with direct contact (no paint)
• under vertical force vector (90-degree angle)
• at room temperature

Determinants of practical lifting force of a magnet

It is worth knowing that the application force will differ subject to the following factors, starting with the most relevant:

• Air gap (betwixt the magnet and the plate), because even a very small clearance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick sheet causes magnetic saturation, causing part of the flux to be lost into the air.
• Material composition – not every steel reacts the same. Alloy additives weaken the interaction with the magnet.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Heat – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.