BM 380x180x70 [4x M8] - magnetic beam

Pros and cons of NdFeB magnets.

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

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
• They possess excellent resistance to magnetism drop due to opposing magnetic fields,
• By using a smooth coating of silver, the element acquires an modern look,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Due to the possibility of accurate forming and adaptation to individualized needs, NdFeB magnets can be modeled in a wide range of forms and dimensions, which makes them more universal,
• Significant place in high-tech industry – they are commonly used in HDD drives, motor assemblies, medical devices, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. 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 those in rubber or plastics, which prevent oxidation and corrosion.
• We recommend a housing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

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

Magnet power was determined for ideal contact conditions, taking into account:

• with the contact of a yoke made of low-carbon steel, ensuring maximum field concentration
• with a cross-section minimum 10 mm
• with a surface free of scratches
• under conditions of ideal adhesion (metal-to-metal)
• under axial force direction (90-degree angle)
• at ambient temperature room level

What influences lifting capacity in practice

Please note that the application force will differ influenced by elements below, in order of importance:

• Air gap (between the magnet and the metal), because even a microscopic clearance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to paint, rust or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Metal type – not every steel attracts identically. High carbon content worsen the interaction with the magnet.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.