UMT 12x20 orange / N38 - board holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their tremendous magnetic power, neodymium magnets offer the following advantages:

• Their power is durable, and after around 10 years, it drops only by ~1% (theoretically),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the brilliant layer of gold, the component looks aesthetically refined,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Thanks to the flexibility in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which increases their application range,
• Wide application in cutting-edge sectors – they find application in hard drives, electric motors, medical equipment along with other advanced devices,
• Thanks to their power density, small magnets offer high magnetic performance, in miniature format,

Disadvantages of NdFeB magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to physical collisions, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage and additionally enhances its overall resistance,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to humidity can rust. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• Limited ability to create internal holes in the magnet – the use of a housing is recommended,
• Safety concern linked to microscopic shards may arise, when consumed by mistake, which is notable in the context of child safety. It should also be noted that small elements from these products may disrupt scanning after being swallowed,
• Due to expensive raw materials, their cost is above average,

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

The given pulling force of the magnet means the maximum force, measured in the best circumstances, that is:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Lifting capacity in real conditions – factors

Practical lifting force is dependent on factors, by priority:

• 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 carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the holding force.