MW 70x60 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They retain full power for around 10 years – the loss is just ~1% (based on simulations),
• Neodymium magnets remain exceptionally resistant to loss of magnetic properties caused by external field sources,
• The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is a distinguishing feature,
• 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...
• In view of the ability of flexible forming and customization to specialized requirements, NdFeB magnets can be produced in a variety of forms and dimensions, which increases their versatility,
• Huge importance in future technologies – they are used in HDD drives, brushless drives, medical equipment, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in compact constructions

What to avoid - cons of neodymium magnets: application proposals

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We recommend casing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex forms.
• Health risk related to microscopic parts of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these products are able to complicate diagnosis medical after entering the body.
• Due to neodymium price, their price is higher than average,

Maximum lifting force for a neodymium magnet – what contributes to it?

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

• with the use of a yoke made of special test steel, ensuring full magnetic saturation
• possessing a massiveness of min. 10 mm to avoid saturation
• with a surface cleaned and smooth
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at room temperature

Magnet lifting force in use – key factors

In practice, the real power results from several key aspects, ranked from the most important:

• Distance (between the magnet and the metal), as even a very small clearance (e.g. 0.5 mm) results in a reduction in force by up to 50% (this also applies to paint, corrosion or debris).
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content reduce magnetic permeability and holding force.
• Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.