MW 6x6 / N38 - cylindrical magnet

Advantages as well as disadvantages of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (based on calculations),
• They feature excellent resistance to weakening of magnetic properties when exposed to external fields,
• By applying a shiny layer of silver, the element acquires an professional look,
• Magnetic induction on the top side of the magnet is exceptional,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Due to the potential of accurate shaping and adaptation to custom requirements, neodymium magnets can be created in a broad palette of forms and dimensions, which increases their versatility,
• Fundamental importance in innovative solutions – they are commonly used in HDD drives, motor assemblies, medical devices, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which enables their usage in compact constructions

Problematic aspects of neodymium magnets and proposals for their use:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited possibility of making nuts in the magnet and complex forms - preferred is casing - magnetic holder.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child health protection. Additionally, tiny parts of these magnets are able to be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is economically unviable,

Optimal lifting capacity of a neodymium magnet – what affects it?

The load parameter shown concerns the peak performance, measured under laboratory conditions, namely:

• using a plate made of mild steel, acting as a ideal flux conductor
• with a thickness of at least 10 mm
• with a plane free of scratches
• with direct contact (no impurities)
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Practical aspects of lifting capacity – factors

Bear in mind that the application force will differ influenced by the following factors, starting with the most relevant:

• Gap (betwixt the magnet and the plate), because even a very small clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, corrosion or debris).
• Angle of force application – maximum parameter is available only during pulling at a 90° angle. The force required to slide of the magnet along the surface is typically many times smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin plate causes magnetic saturation, causing part of the flux to be escaped to the other side.
• Material type – the best choice is high-permeability steel. Stainless steels may attract less.
• Surface finish – full contact is obtained only on smooth steel. Rough texture create air cushions, reducing force.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity was determined using a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.