BM 320x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of rare earth magnets.

Besides their tremendous pulling force, neodymium magnets offer the following advantages:

• Their strength remains stable, and after around 10 years it drops only by ~1% (theoretically),
• Magnets very well defend themselves against loss of magnetization caused by ambient magnetic noise,
• The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• They show high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Possibility of precise forming as well as adjusting to specific requirements,
• Key role in high-tech industry – they are commonly used in computer drives, electric motors, medical equipment, and technologically advanced constructions.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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
• They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing nuts and complicated shapes in magnets, we recommend using cover - magnetic holder.
• Possible danger related to microscopic parts of magnets pose a threat, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small components of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Due to expensive raw materials, their price is higher than average,

Maximum holding power of the magnet – what contributes to it?

The declared magnet strength concerns the maximum value, recorded under laboratory conditions, namely:

• on a base made of structural steel, optimally conducting the magnetic flux
• with a thickness no less than 10 mm
• with an polished contact surface
• under conditions of ideal adhesion (metal-to-metal)
• during detachment in a direction vertical to the plane
• in stable room temperature

Lifting capacity in practice – influencing factors

It is worth knowing that the working load may be lower subject to the following factors, starting with the most relevant:

• Air gap (between the magnet and the metal), since even a tiny distance (e.g. 0.5 mm) results in a reduction in force by up to 50% (this also applies to varnish, rust or debris).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick sheet does not close the flux, causing part of the flux to be wasted into the air.
• Steel type – mild steel gives the best results. Higher carbon content reduce magnetic permeability and lifting capacity.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Thermal factor – high temperature reduces pulling force. Too high temperature can permanently demagnetize the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the lifting capacity.