AM lina fi 10 mm - magnetic accessories

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (based on calculations),
• They are extremely resistant to demagnetization caused by external magnetic fields,
• The use of a polished nickel surface provides a smooth finish,
• They have exceptional magnetic induction on the surface of the magnet,
• With the right combination of magnetic alloys, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the form),
• With the option for tailored forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Key role in cutting-edge sectors – they find application in data storage devices, electric drives, medical equipment along with technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in compact dimensions, which makes them useful in small systems

Disadvantages of rare earth magnets:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to shocks, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall robustness,
• High temperatures may significantly reduce the magnetic power 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 wet conditions can corrode. Therefore, for outdoor applications, we advise waterproof types made of non-metallic composites,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing complex structures directly in the magnet,
• Potential hazard due to small fragments may arise, especially if swallowed, which is important in the health of young users. Moreover, miniature parts from these assemblies have the potential to interfere with diagnostics once in the system,
• In cases of large-volume purchasing, neodymium magnet cost may not be economically viable,

Magnetic strength at its maximum – what contributes to it?

The given holding capacity of the magnet means the highest holding force, determined in the best circumstances, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

Lifting capacity in practice – influencing 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) 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet and the plate reduces the lifting capacity.