HH 16x5.3 [M3] / N38 - through hole magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their magnetic properties for around ten years – the loss is just ~1% (based on simulations),
• Their ability to resist magnetic interference from external fields is impressive,
• The use of a decorative nickel surface provides a refined finish,
• They have extremely strong magnetic induction on the surface 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 tailored forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Significant impact in cutting-edge sectors – they find application in HDDs, electromechanical systems, diagnostic apparatus as well as sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in compact dimensions, which makes them ideal in compact constructions

Disadvantages of magnetic elements:

• They can break when subjected to a strong impact. If the magnets are exposed to shocks, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture while also strengthens its overall strength,
• High temperatures may significantly reduce the holding force 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,
• They rust in a wet environment – during outdoor use, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create threads in the magnet – the use of a external casing is recommended,
• Possible threat from tiny pieces may arise, especially if swallowed, which is crucial in the family environments. Furthermore, minuscule fragments from these magnets may hinder health screening when ingested,
• Due to the price of neodymium, their cost is relatively high,

Detachment force of the magnet in optimal conditions – what contributes to it?

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

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• with no separation
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is conditioned by the following aspects, from crucial to less important:

• 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 testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the load capacity.