UI 17.5x5 [C310] / N38 - badge holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after 10 years, the performance loss is only ~1% (in laboratory conditions),
• They protect against demagnetization induced by ambient magnetic influence remarkably well,
• The use of a decorative silver surface provides a eye-catching finish,
• They exhibit elevated 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,
• With the option for fine forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving engineering flexibility,
• Important function in modern technologies – they find application in hard drives, electromechanical systems, medical equipment and other advanced devices,
• Thanks to their power density, small magnets offer high magnetic performance, in miniature format,

Disadvantages of rare earth magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to mechanical hits, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage while also enhances its overall robustness,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent degradation 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,
• They rust in a moist environment – during outdoor use, we recommend using sealed magnets, such as those made of plastic,
• Limited ability to create complex details in the magnet – the use of a housing is recommended,
• Possible threat due to small fragments may arise, especially if swallowed, which is significant in the family environments. Additionally, tiny components from these assemblies have the potential to hinder health screening after being swallowed,
• In cases of tight budgets, neodymium magnet cost may not be economically viable,

Maximum holding power of the magnet – what it depends on?

The given strength of the magnet corresponds to the optimal strength, assessed in the best circumstances, namely:

• 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
• under perpendicular detachment force
• at room temperature

Determinants of practical lifting force of a magnet

The lifting capacity of a magnet depends on in practice key elements, ordered from most important to least significant:

• Air gap between the magnet and the plate, because 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.

* Lifting capacity was measured by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.