UMP 65x45 [M8]x2 GW / N38 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their remarkable pulling force, neodymium magnets offer the following advantages:

• Their strength remains stable, and after around 10 years, it drops only by ~1% (according to research),
• They show exceptional resistance to demagnetization from outside magnetic sources,
• Thanks to the glossy finish and nickel coating, they have an aesthetic appearance,
• They exhibit extremely high 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,
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which increases their functional possibilities,
• Significant impact in new technology industries – they are utilized in hard drives, electric motors, medical equipment as well as sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which allows for use in miniature devices

Disadvantages of magnetic elements:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to shocks, we recommend 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 decline in performance (depending on shape). 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 humidity can corrode. Therefore, for outdoor applications, we advise waterproof types made of rubber,
• Limited ability to create internal holes in the magnet – the use of a magnetic holder is recommended,
• Health risk related to magnet particles may arise, especially if swallowed, which is significant in the protection of children. Additionally, small elements from these magnets may complicate medical imaging when ingested,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which may limit large-scale applications

Magnetic strength at its maximum – what contributes to it?

The given holding capacity of the magnet means the highest holding force, assessed under optimal conditions, that is:

• 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
• with vertical force applied
• at room temperature

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• Air gap between the magnet and the plate, because 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 was determined by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.