MW 14x10 / N38 - cylindrical magnet

Strengths as well as weaknesses of NdFeB magnets.

Besides their exceptional pulling force, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
• They possess excellent resistance to magnetic field loss when exposed to external fields,
• A magnet with a shiny gold surface is more attractive,
• Magnets are characterized by exceptionally strong magnetic induction on the outer side,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Thanks to versatility in constructing and the ability to modify to unusual requirements,
• Significant place in high-tech industry – they find application in HDD drives, electric motors, medical equipment, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. 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 immune to moisture, in case of application outdoors
• We suggest casing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complicated forms.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which is particularly important in the context of child health protection. It is also worth noting that small elements of these magnets can complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Detachment force of the magnet in optimal conditions – what contributes to it?

The load parameter shown refers to the maximum value, recorded under ideal test conditions, specifically:

• with the use of a yoke made of special test steel, ensuring full magnetic saturation
• possessing a massiveness of min. 10 mm to avoid saturation
• with a plane free of scratches
• with total lack of distance (no paint)
• during detachment in a direction perpendicular to the plane
• at standard ambient temperature

Practical lifting capacity: influencing factors

During everyday use, the actual holding force is determined by a number of factors, presented from the most important:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Smoothness – full contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Thermal environment – temperature increase results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under parallel forces the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.