MW 6x2 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for nearly 10 years – the loss is just ~1% (based on simulations),
• They are extremely resistant to demagnetization caused by external magnetic sources,
• Because of the brilliant layer of gold, the component looks high-end,
• The outer field strength of the magnet shows elevated magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for precise shaping and adjustment to custom needs – neodymium magnets can be manufactured in many forms and dimensions, which amplifies their functionality across industries,
• Important function in new technology industries – they are used in data storage devices, electromechanical systems, medical equipment and technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage while also enhances its overall robustness,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent weakening 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,
• They rust in a damp environment, especially when used outside, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create complex details in the magnet – the use of a mechanical support is recommended,
• Health risk from tiny pieces may arise, especially if swallowed, which is significant in the family environments. Furthermore, small elements from these assemblies can interfere with diagnostics if inside the body,
• In cases of tight budgets, neodymium magnet cost may be a barrier,

Best holding force of the magnet in ideal parameters – what affects it?

The given lifting capacity of the magnet corresponds to the maximum lifting force, assessed under optimal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Determinants of practical lifting force of a magnet

In practice, the holding capacity of a magnet is affected by these factors, from crucial to less important:

• 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, however under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate decreases the holding force.