BM 380x180x70 [4x M8] - magnetic beam

Pros and cons of rare earth magnets.

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

• They have constant strength, and over nearly ten years their performance decreases symbolically – ~1% (according to theory),
• Neodymium magnets are extremely resistant to demagnetization caused by external field sources,
• In other words, due to the reflective finish of silver, the element gains visual value,
• The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to modularity in designing and the capacity to customize to client solutions,
• Key role in advanced technology sectors – they serve a role in computer drives, electromotive mechanisms, advanced medical instruments, and technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• NdFeB 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
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited possibility of producing nuts in the magnet and complex shapes - preferred is a housing - magnetic holder.
• Potential hazard to health – tiny shards 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 components of these products can disrupt the diagnostic process medical after entering the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Best holding force of the magnet in ideal parameters – what contributes to it?

The declared magnet strength represents the maximum value, recorded under laboratory conditions, specifically:

• on a plate made of structural steel, optimally conducting the magnetic field
• possessing a thickness of at least 10 mm to ensure full flux closure
• with an ideally smooth touching surface
• with zero gap (without impurities)
• under axial application of breakaway force (90-degree angle)
• in temp. approx. 20°C

Key elements affecting lifting force

In real-world applications, the actual holding force depends on many variables, presented from the most important:

• Air gap (between the magnet and the plate), as even a tiny distance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel type – low-carbon steel attracts best. Alloy steels reduce magnetic permeability and holding force.
• Surface finish – full contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet’s surface and the plate lowers the holding force.