BM 950x180x70 [4x M8] - magnetic beam

Strengths and weaknesses of neodymium magnets.

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

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (according to theory),
• They are resistant to demagnetization induced by external magnetic fields,
• By applying a reflective coating of silver, the element presents an elegant look,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• 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 freedom in constructing and the ability to modify to specific needs,
• Significant place in modern technologies – they are used in hard drives, drive modules, diagnostic systems, as well as industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets and ways of using them

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a special holder, which not only protects them against impacts but also raises their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited ability of creating threads in the magnet and complicated shapes - recommended is casing - magnet mounting.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small components of these products can be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price is higher than average,

Maximum lifting force for a neodymium magnet – what it depends on?

Breakaway force was defined for optimal configuration, assuming:

• on a base made of structural steel, effectively closing the magnetic flux
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a plane cleaned and smooth
• under conditions of ideal adhesion (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Practical aspects of lifting capacity – factors

In practice, the real power is determined by a number of factors, ranked from the most important:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – too thin plate causes magnetic saturation, causing part of the flux to be escaped to the other side.
• Steel grade – the best choice is pure iron steel. Hardened steels may attract less.
• Plate texture – smooth surfaces guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed using a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.