BM 380x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of NdFeB magnets.

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

• They have constant strength, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
• They are resistant to demagnetization induced by external disturbances,
• The use of an metallic coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures approaching 230°C and above...
• Thanks to modularity in designing and the ability to modify to client solutions,
• Key role in modern industrial fields – they find application in computer drives, electric motors, medical equipment, also modern systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in compact constructions

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in strength. 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
• They oxidize in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complicated forms in magnets, we recommend using cover - magnetic holder.
• Health risk related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. It is also worth noting that small components of these products are able to complicate diagnosis medical in case of swallowing.
• Due to expensive raw materials, their price exceeds standard values,

Magnetic strength at its maximum – what contributes to it?

Information about lifting capacity was determined for ideal contact conditions, including:

• on a block made of mild steel, effectively closing the magnetic field
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• with an polished touching surface
• with direct contact (without paint)
• during pulling in a direction perpendicular to the mounting surface
• in temp. approx. 20°C

Magnet lifting force in use – key factors

In real-world applications, the actual lifting capacity results from many variables, ranked from crucial:

• Distance (betwixt the magnet and the metal), as even a very small distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Direction of force – highest force is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin sheet does not close the flux, causing part of the power to be lost to the other side.
• Plate material – low-carbon steel gives the best results. Higher carbon content reduce magnetic properties and lifting capacity.
• Base smoothness – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – heating the magnet results in weakening of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under a perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the holding force.