MW 45x35 / N38 - cylindrical magnet

Pros as well as cons of rare earth magnets.

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

• They have constant strength, and over nearly ten years their attraction force decreases symbolically – ~1% (according to theory),
• They feature excellent resistance to magnetism drop when exposed to opposing magnetic fields,
• The use of an metallic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in designing and the ability to adapt to unusual requirements,
• Fundamental importance in future technologies – they are used in data components, brushless drives, diagnostic systems, also modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Cons of neodymium magnets: application proposals

• To avoid cracks under impact, we recommend using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in realizing threads and complex shapes in magnets, we propose using casing - magnetic holder.
• Health risk to health – tiny shards of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, tiny parts of these devices are able to be problematic in diagnostics medical when they are in the body.
• With budget limitations the cost of neodymium magnets is economically unviable,

Magnetic strength at its maximum – what affects it?

Breakaway force was determined for optimal configuration, assuming:

• on a base made of mild steel, effectively closing the magnetic field
• whose thickness equals approx. 10 mm
• with an ground contact surface
• with direct contact (no coatings)
• under axial application of breakaway force (90-degree angle)
• at room temperature

Magnet lifting force in use – key factors

In real-world applications, the actual lifting capacity depends on several key aspects, listed from the most important:

• Distance – the presence of any layer (rust, tape, gap) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Angle of force application – highest force is reached only during pulling at a 90° angle. The force required to slide of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – mild steel gives the best results. Alloy admixtures decrease magnetic permeability and holding force.
• Surface finish – full contact is possible only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.