BM 380x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets.

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

• They do not lose strength, even over around ten years – the drop in strength is only ~1% (theoretically),
• Magnets very well defend themselves against demagnetization caused by foreign field sources,
• In other words, due to the glossy surface of silver, the element looks attractive,
• Neodymium magnets create maximum magnetic induction on a small area, which ensures high operational effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to freedom in designing and the capacity to modify to client solutions,
• Versatile presence in innovative solutions – they are used in HDD drives, brushless drives, advanced medical instruments, as well as multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also raises their durability
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape as well as 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. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic holder, due to difficulties in creating threads inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child safety. It is also worth noting that small components of these magnets are able to be problematic in diagnostics medical after entering the body.
• Due to complex production process, their price is higher than average,

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

Information about lifting capacity was defined for the most favorable conditions, taking into account:

• using a plate made of low-carbon steel, acting as a ideal flux conductor
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by smoothness
• without any air gap between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Lifting capacity in real conditions – factors

In real-world applications, the actual lifting capacity results from many variables, listed from most significant:

• Gap (between the magnet and the metal), as even a tiny clearance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – maximum parameter is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick plate does not accept the full field, causing part of the power to be wasted to the other side.
• Steel grade – the best choice is high-permeability steel. Cast iron may generate lower lifting capacity.
• Smoothness – full contact is obtained only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Temperature – temperature increase causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Holding force was checked on a smooth steel plate 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 fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.