BM 380x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of NdFeB magnets.

Apart from their consistent power, neodymium magnets have these key benefits:

• They do not lose power, even after around 10 years – the drop in strength is only ~1% (according to tests),
• Magnets perfectly defend themselves against loss of magnetization caused by external fields,
• In other words, due to the smooth layer of gold, the element looks attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Possibility of detailed forming and adjusting to precise needs,
• Universal use in innovative solutions – they serve a role in data components, brushless drives, advanced medical instruments, also modern systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. 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
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in producing threads and complicated forms in magnets, we recommend using casing - magnetic holder.
• Health risk related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that tiny parts of these devices can complicate diagnosis medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The force parameter is a theoretical maximum value conducted under standard conditions:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• with a cross-section of at least 10 mm
• with an ground contact surface
• with direct contact (without coatings)
• during detachment in a direction vertical to the mounting surface
• in neutral thermal conditions

Key elements affecting lifting force

In real-world applications, the actual holding force is determined by a number of factors, presented from the most important:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface structure – the smoother and more polished the surface, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate decreases the holding force.