BM 380x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of rare earth magnets.

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

• Their power is maintained, and after approximately ten years it drops only by ~1% (according to research),
• Magnets effectively protect themselves against loss of magnetization caused by ambient magnetic noise,
• A magnet with a shiny silver surface is more attractive,
• Magnets are characterized by extremely high magnetic induction on the active area,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to versatility in designing and the ability to modify to specific needs,
• Fundamental importance in high-tech industry – they serve a role in computer drives, electromotive mechanisms, advanced medical instruments, and industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures 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 extremely resistant to heat
• They oxidize in a humid environment - during 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 mount.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these products can be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Highest magnetic holding force – what contributes to it?

Information about lifting capacity was defined for the most favorable conditions, including:

• with the use of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• with a cross-section of at least 10 mm
• with a plane free of scratches
• with direct contact (no paint)
• under vertical force direction (90-degree angle)
• at standard ambient temperature

What influences lifting capacity in practice

Real force is affected by working environment parameters, mainly (from most important):

• Distance (betwixt the magnet and the plate), as even a very small clearance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to varnish, rust or debris).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel attracts identically. High carbon content weaken the interaction with the magnet.
• Surface structure – the more even the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was measured by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, however under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate decreases the holding force.