MT 50x1.5x30000 - magnetic tape

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They do not lose their strength nearly ten years – the loss of strength is only ~1% (theoretically),
• They protect against demagnetization induced by external magnetic influence very well,
• Because of the brilliant layer of gold, the component looks aesthetically refined,
• They possess strong magnetic force measurable at the magnet’s surface,
• Thanks to their exceptional temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• The ability for custom shaping and adjustment to individual needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Key role in cutting-edge sectors – they serve a purpose in HDDs, electric drives, medical equipment as well as sophisticated instruments,
• 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, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time reinforces its overall resistance,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on size). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we suggest waterproof types made of non-metallic composites,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing threads directly in the magnet,
• Health risk due to small fragments may arise, when consumed by mistake, which is crucial in the context of child safety. It should also be noted that minuscule fragments from these devices have the potential to hinder health screening when ingested,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

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

The given lifting capacity of the magnet represents the maximum lifting force, calculated in ideal conditions, namely:

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a smooth surface
• in conditions of no clearance
• with vertical force applied
• at room temperature

Magnet lifting force in use – key factors

Practical lifting force is determined by factors, by priority:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.