MW 10x20 / N38 - cylindrical magnet

Strengths and weaknesses of neodymium magnets.

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

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They have excellent resistance to weakening of magnetic properties due to opposing magnetic fields,
• In other words, due to the metallic layer of gold, the element is aesthetically pleasing,
• Neodymium magnets generate maximum magnetic induction on a small surface, which allows for strong attraction,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• In view of the ability of free shaping and customization to individualized requirements, NdFeB magnets can be created in a variety of shapes and sizes, which amplifies use scope,
• Wide application in electronics industry – they find application in mass storage devices, electric motors, medical equipment, also modern systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which enables their usage in compact constructions

What to avoid - cons of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited possibility of creating threads in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Potential hazard to health – tiny shards of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child health protection. Furthermore, tiny parts of these products are able to be problematic in diagnostics medical when they are in the body.
• Due to expensive raw materials, their price is relatively high,

Detachment force of the magnet in optimal conditions – what affects it?

Holding force of 11.06 kg is a result of laboratory testing conducted under the following configuration:

• with the use of a yoke made of special test steel, guaranteeing full magnetic saturation
• whose thickness is min. 10 mm
• with a surface cleaned and smooth
• without any insulating layer between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

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

• Clearance – the presence of foreign body (paint, tape, gap) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Uneven metal weaken the grip.
• Temperature – heating the magnet results in weakening of induction. Check the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.