MW 5x7 / N38 - cylindrical magnet

Strengths as well as weaknesses of NdFeB magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• Neodymium magnets remain exceptionally resistant to demagnetization caused by magnetic disturbances,
• By covering with a lustrous layer of nickel, the element presents an proper look,
• Magnetic induction on the top side of the magnet turns out to be extremely intense,
• 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 versatility in designing and the capacity to modify to client solutions,
• Wide application in advanced technology sectors – they are used in data components, drive modules, precision medical tools, as well as industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They oxidize in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing nuts and complex shapes in magnets, we propose using casing - magnetic mechanism.
• Health risk to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that tiny parts of these devices are able to be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what affects it?

The load parameter shown refers to the peak performance, measured under optimal environment, namely:

• using a plate made of high-permeability steel, acting as a circuit closing element
• whose thickness reaches at least 10 mm
• with an ideally smooth touching surface
• with zero gap (no coatings)
• for force applied at a right angle (in the magnet axis)
• at room temperature

Lifting capacity in practice – influencing factors

During everyday use, the real power depends on many variables, ranked from most significant:

• Distance – the presence of any layer (rust, dirt, air) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick plate does not accept the full field, causing part of the flux to be escaped into the air.
• Chemical composition of the base – mild steel gives the best results. Alloy steels reduce magnetic properties and lifting capacity.
• Smoothness – ideal contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet and the plate lowers the holding force.