MPL 20x8x4 / N38 - lamellar magnet

Pros and cons of neodymium magnets.

Besides their immense magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over nearly 10 years their performance decreases symbolically – ~1% (according to theory),
• They retain their magnetic properties even under close interference source,
• By covering with a reflective layer of nickel, the element presents an elegant look,
• Magnets possess huge magnetic induction on the active area,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in constructing and the capacity to modify to specific needs,
• Universal use in innovative solutions – they find application in HDD drives, drive modules, diagnostic systems, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in small systems

What to avoid - cons of neodymium magnets and ways of using them

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose their force 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in producing nuts and complicated shapes in magnets, we propose using cover - magnetic holder.
• Health risk to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. Additionally, small elements of these magnets can disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

Information about lifting capacity was defined for ideal contact conditions, including:

• on a base made of structural steel, optimally conducting the magnetic field
• with a cross-section no less than 10 mm
• characterized by lack of roughness
• with direct contact (no paint)
• under axial force direction (90-degree angle)
• at room temperature

Lifting capacity in real conditions – factors

Please note that the working load may be lower depending on the following factors, in order of importance:

• Air gap (between the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Angle of force application – maximum parameter is available only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly 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 attraction force (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Hardened steels may attract less.
• Surface finish – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on a smooth plate of optimal thickness, under a perpendicular pulling force, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet and the plate lowers the holding force.