NCM 40x13.5x5 / N38 - channel magnetic holder

Strengths as well as weaknesses of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They retain full power for nearly 10 years – the loss is just ~1% (in theory),
• They feature excellent resistance to magnetic field loss when exposed to external fields,
• By using a reflective coating of gold, the element gains an professional look,
• Magnetic induction on the surface of the magnet remains maximum,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures approaching 230°C and above...
• Possibility of accurate creating and modifying to defined requirements,
• Significant place in modern technologies – they serve a role in data components, electric motors, diagnostic systems, as well as other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of producing nuts in the magnet and complicated shapes - recommended is a housing - magnetic holder.
• Potential hazard to health – tiny shards of magnets pose a threat, in case of ingestion, which is particularly important in the context of child health protection. It is also worth noting that small elements of these products can be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is a challenge,

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

The specified lifting capacity represents the limit force, measured under laboratory conditions, specifically:

• on a plate made of structural steel, perfectly concentrating the magnetic flux
• with a cross-section minimum 10 mm
• characterized by lack of roughness
• with direct contact (without impurities)
• under axial force vector (90-degree angle)
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

In practice, the actual holding force depends on several key aspects, ranked from the most important:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Material composition – not every steel reacts the same. High carbon content worsen the attraction effect.
• Smoothness – full contact is obtained only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature – temperature increase causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under parallel forces the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.