UI 45x13x6 [C321] / N38 - badge holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their full power for nearly ten years – the drop is just ~1% (based on simulations),
• They remain magnetized despite exposure to strong external fields,
• Thanks to the shiny finish and silver coating, they have an elegant appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the form),
• The ability for accurate shaping or adaptation to specific needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Key role in advanced technical fields – they serve a purpose in data storage devices, rotating machines, clinical machines and high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in compact dimensions, which makes them useful in compact constructions

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to shocks, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture and additionally increases its overall robustness,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on form). 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 humid environment. If exposed to rain, we recommend using moisture-resistant magnets, such as those made of non-metallic materials,
• Limited ability to create precision features in the magnet – the use of a magnetic holder is recommended,
• Potential hazard from tiny pieces may arise, when consumed by mistake, which is important in the context of child safety. Additionally, small elements from these assemblies might interfere with diagnostics if inside the body,
• Due to the price of neodymium, their cost is considerably higher,

Maximum lifting force for a neodymium magnet – what it depends on?

The given lifting capacity of the magnet means the maximum lifting force, assessed under optimal conditions, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Determinants of practical lifting force of a magnet

In practice, the holding capacity of a magnet is affected by the following aspects, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, as 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 conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet and the plate reduces the load capacity.