NCM 15x13.5x5 / N38 - channel magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their full power for nearly 10 years – the drop is just ~1% (based on simulations),
• They are highly resistant to demagnetization caused by external magnetic sources,
• Thanks to the polished finish and nickel coating, they have an aesthetic appearance,
• They have extremely strong magnetic induction on the surface of the magnet,
• Thanks to their exceptional temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• The ability for accurate shaping as well as adaptation to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Key role in cutting-edge sectors – they are utilized in data storage devices, rotating machines, medical equipment and high-tech tools,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time strengthens its overall strength,
• They lose field intensity at elevated temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to moisture can oxidize. Therefore, for outdoor applications, we suggest waterproof types made of rubber,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is not feasible,
• Possible threat linked to microscopic shards may arise, when consumed by mistake, which is important in the family environments. It should also be noted that miniature parts from these products might disrupt scanning if inside the body,
• In cases of mass production, neodymium magnet cost may be a barrier,

Maximum lifting capacity of the magnet – what contributes to it?

The given strength of the magnet represents the optimal strength, measured in the best circumstances, that is:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• with vertical force applied
• in normal thermal conditions

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is conditioned by these factors, in descending order of importance:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, however under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.