UMT 12x20 purple / N38 - board holder

Strengths and weaknesses of rare earth magnets.

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

• They do not lose strength, even after approximately ten years – the reduction in strength is only ~1% (theoretically),
• Magnets very well protect themselves against demagnetization caused by external fields,
• Thanks to the shimmering finish, the coating of Ni-Cu-Ni, gold, or silver gives an modern appearance,
• Magnetic induction on the working part of the magnet remains maximum,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Thanks to flexibility in designing and the capacity to customize to specific needs,
• Versatile presence in modern technologies – they are utilized in data components, electric drive systems, diagnostic systems, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a special holder, which not only secures them against impacts but also increases their durability
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 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 and corrosion.
• We suggest casing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complex shapes.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child safety. Furthermore, small components of these magnets can complicate diagnosis medical after entering the body.
• With mass production the cost of neodymium magnets can be a barrier,

Maximum lifting force for a neodymium magnet – what it depends on?

Magnet power is the result of a measurement for the most favorable conditions, including:

• with the use of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• whose thickness reaches at least 10 mm
• with a surface free of scratches
• without any clearance between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at standard ambient temperature

Magnet lifting force in use – key factors

During everyday use, the actual lifting capacity depends on a number of factors, ranked from most significant:

• Air gap (betwixt the magnet and the plate), as even a tiny distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Angle of force application – maximum parameter is obtained only during pulling at a 90° angle. The shear force of the magnet along the surface is usually several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Plate material – mild steel gives the best results. Higher carbon content decrease magnetic permeability and holding force.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet and the plate reduces the load capacity.