NCM 10x13.5x5 / N38 - channel magnetic holder

Advantages and disadvantages of rare earth magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• Magnets very well resist against loss of magnetization caused by foreign field sources,
• The use of an shiny coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures reaching 230°C and above...
• Thanks to the option of accurate molding and customization to individualized needs, NdFeB magnets can be created in a wide range of shapes and sizes, which expands the range of possible applications,
• Significant place in modern industrial fields – they find application in mass storage devices, motor assemblies, precision medical tools, and technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which allows their use in small systems

Cons of neodymium magnets and proposals for their use:

• At strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength 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 corrode. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of creating threads in the magnet and complicated forms - preferred is a housing - magnetic holder.
• Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Furthermore, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Optimal lifting capacity of a neodymium magnet – what affects it?

Magnet power was defined for optimal configuration, including:

• using a plate made of low-carbon steel, acting as a magnetic yoke
• with a cross-section minimum 10 mm
• characterized by lack of roughness
• under conditions of no distance (surface-to-surface)
• under vertical force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

Effective lifting capacity impacted by specific conditions, including (from priority):

• Clearance – the presence of foreign body (paint, dirt, gap) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Cast iron may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• Thermal environment – heating the magnet causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.