MP 5x2.7/1.2x5 C / N38 - ring magnet

Advantages as well as disadvantages of rare earth magnets.

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

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Neodymium magnets prove to be extremely resistant to loss of magnetic properties caused by magnetic disturbances,
• Thanks to the shiny finish, the layer of Ni-Cu-Ni, gold, or silver gives an elegant appearance,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of detailed forming and modifying to specific requirements,
• Universal use in innovative solutions – they are used in magnetic memories, electric motors, advanced medical instruments, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in creating threads and complex shapes in magnets, we recommend using casing - magnetic mount.
• Potential hazard to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is economically unviable,

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

The load parameter shown represents the maximum value, measured under ideal test conditions, specifically:

• on a block made of structural steel, optimally conducting the magnetic flux
• with a cross-section no less than 10 mm
• characterized by smoothness
• with total lack of distance (without impurities)
• under vertical force vector (90-degree angle)
• at room temperature

Determinants of lifting force in real conditions

In practice, the actual lifting capacity is determined by many variables, ranked from most significant:

• Clearance – the presence of any layer (rust, tape, gap) interrupts the magnetic circuit, which reduces power rapidly (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the power to be escaped to the other side.
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures decrease magnetic permeability and holding force.
• Surface quality – the smoother and more polished the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Temperature – temperature increase causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was determined using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, in contrast under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet and the plate reduces the load capacity.