MW 6x6 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• Their magnetic field is durable, and after approximately 10 years it decreases only by ~1% (theoretically),
• They are resistant to demagnetization induced by external magnetic fields,
• Thanks to the shiny finish, the layer of Ni-Cu-Ni, gold, or silver-plated gives an aesthetic appearance,
• Magnets are characterized by extremely high magnetic induction on the outer layer,
• 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...
• Possibility of custom shaping and modifying to defined requirements,
• Wide application in modern industrial fields – they are used in HDD drives, electric motors, diagnostic systems, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in miniature devices

What to avoid - cons of neodymium magnets: application proposals

• At strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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 extremely resistant to heat
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Due to limitations in producing nuts and complicated shapes in magnets, we recommend using casing - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which becomes key in the context of child safety. Additionally, small elements of these devices can be problematic in diagnostics medical when they are in the body.
• With mass production the cost of neodymium magnets can be a barrier,

Maximum holding power of the magnet – what contributes to it?

Magnet power was defined for ideal contact conditions, taking into account:

• using a plate made of low-carbon steel, serving as a circuit closing element
• whose thickness is min. 10 mm
• with an polished touching surface
• under conditions of gap-free contact (surface-to-surface)
• during pulling in a direction perpendicular to the mounting surface
• at standard ambient temperature

Lifting capacity in practice – influencing factors

In real-world applications, the actual holding force depends on a number of factors, listed from the most important:

• Space between magnet and steel – every millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Steel thickness – too thin plate does not accept the full field, causing part of the flux to be wasted into the air.
• Material composition – different alloys attracts identically. Alloy additives weaken the interaction with the magnet.
• Smoothness – full contact is possible only on polished steel. Rough texture reduce the real contact area, reducing force.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate lowers the load capacity.