BM 650x180x70 [4x M8] - magnetic beam

Strengths and weaknesses of neodymium magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• Their strength is durable, and after approximately 10 years it drops only by ~1% (theoretically),
• They show high resistance to demagnetization induced by external disturbances,
• By applying a shiny layer of silver, the element presents an nice look,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Thanks to flexibility in forming and the ability to customize to unusual requirements,
• Huge importance in modern industrial fields – they are used in computer drives, brushless drives, advanced medical instruments, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in small systems

What to avoid - cons of neodymium magnets: tips and applications.

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• Due to limitations in creating threads and complicated shapes in magnets, we recommend using a housing - magnetic mechanism.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the context of child health protection. It is also worth noting that small elements of these devices can be problematic in diagnostics medical when they are in the body.
• Due to expensive raw materials, their price is relatively high,

Magnetic strength at its maximum – what it depends on?

The load parameter shown concerns the maximum value, obtained under optimal environment, namely:

• using a plate made of low-carbon steel, serving as a circuit closing element
• with a cross-section of at least 10 mm
• characterized by smoothness
• without the slightest insulating layer between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

It is worth knowing that the magnet holding will differ influenced by the following factors, in order of importance:

• Distance (betwixt the magnet and the plate), because even a tiny clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, rust or dirt).
• Direction of force – maximum parameter is reached only during pulling at a 90° angle. The force required to slide of the magnet along the plate is typically many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin plate causes magnetic saturation, causing part of the flux to be escaped into the air.
• Metal type – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.