MP 12x8/4x3 / N38 - ring magnet

Pros as well as cons of rare earth magnets.

Apart from their superior holding force, neodymium magnets have these key benefits:

• They retain attractive force for almost ten years – the loss is just ~1% (based on simulations),
• They have excellent resistance to weakening of magnetic properties as a result of external magnetic sources,
• Thanks to the shimmering finish, the coating of Ni-Cu-Ni, gold, or silver gives an clean appearance,
• Magnetic induction on the working layer of the magnet is strong,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Thanks to the possibility of precise forming and adaptation to specialized requirements, magnetic components can be created in a variety of shapes and sizes, which makes them more universal,
• Fundamental importance in modern technologies – they find application in magnetic memories, electric drive systems, advanced medical instruments, also multitasking production systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Problematic aspects of neodymium magnets and ways of using them

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in creating nuts and complicated shapes in magnets, we propose using a housing - magnetic mechanism.
• Possible danger resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child health protection. Additionally, small elements of these products are able to disrupt the diagnostic process medical after entering the body.
• Due to expensive raw materials, their price is higher than average,

Magnetic strength at its maximum – what affects it?

The declared magnet strength refers to the maximum value, obtained under optimal environment, meaning:

• with the contact of a sheet made of special test steel, guaranteeing full magnetic saturation
• whose thickness reaches at least 10 mm
• characterized by lack of roughness
• with total lack of distance (no coatings)
• for force applied at a right angle (pull-off, not shear)
• at temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

Holding efficiency impacted by working environment parameters, mainly (from priority):

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When attempting to slide, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Metal type – different alloys attracts identically. High carbon content worsen the attraction effect.
• Surface finish – ideal contact is possible only on polished steel. Rough texture create air cushions, reducing force.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet’s surface and the plate decreases the holding force.