MW 2x4 / N38 - cylindrical magnet

Advantages as well as disadvantages of rare earth magnets.

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

• Their strength is maintained, and after around ten years it drops only by ~1% (according to research),
• They possess excellent resistance to magnetism drop due to opposing magnetic fields,
• A magnet with a metallic gold surface has better aesthetics,
• Magnetic induction on the working layer of the magnet remains exceptional,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of custom shaping and optimizing to complex conditions,
• Key role in innovative solutions – they are used in computer drives, brushless drives, precision medical tools, as well as multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in miniature devices

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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 very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• We recommend a housing - magnetic mount, due to difficulties in creating nuts inside the magnet and complicated forms.
• Health risk resulting from small fragments of magnets are risky, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these devices are able to disrupt the diagnostic process medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

Highest magnetic holding force – what contributes to it?

Holding force of 0.44 kg is a measurement result executed under standard conditions:

• on a base made of mild steel, perfectly concentrating the magnetic flux
• whose thickness reaches at least 10 mm
• characterized by even structure
• without the slightest clearance between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at conditions approx. 20°C

Key elements affecting lifting force

In practice, the real power depends on several key aspects, ranked from most significant:

• Distance – the presence of foreign body (rust, tape, gap) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Metal type – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Base smoothness – the more even the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Temperature – heating the magnet causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet and the plate lowers the load capacity.