BM 380x180x70 [4x M8] - magnetic beam

Pros as well as cons of NdFeB magnets.

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

• They do not lose power, even after around ten years – the drop in strength is only ~1% (according to tests),
• Neodymium magnets are characterized by extremely resistant to magnetic field loss caused by magnetic disturbances,
• A magnet with a smooth silver surface is more attractive,
• Magnetic induction on the surface of the magnet turns out to be impressive,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to modularity in designing and the capacity to customize to individual projects,
• Wide application in modern technologies – they are commonly used in mass storage devices, electromotive mechanisms, medical devices, as well as modern systems.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited ability of making threads in the magnet and complex shapes - preferred is a housing - mounting mechanism.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Furthermore, small components of these devices are able to be problematic in diagnostics medical in case of swallowing.
• With budget limitations the cost of neodymium magnets is economically unviable,

Optimal lifting capacity of a neodymium magnet – what affects it?

The lifting capacity listed is a result of laboratory testing performed under specific, ideal conditions:

• using a base made of high-permeability steel, serving as a magnetic yoke
• whose transverse dimension reaches at least 10 mm
• characterized by lack of roughness
• with zero gap (no coatings)
• under vertical application of breakaway force (90-degree angle)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

In real-world applications, the real power is determined by a number of factors, presented from most significant:

• Air gap (between the magnet and the plate), as even a very small clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – too thin steel does not close the flux, causing part of the flux to be wasted into the air.
• Steel grade – the best choice is high-permeability steel. Hardened steels may attract less.
• Surface finish – full contact is possible only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Heat – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity was determined with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the holding force is lower. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.