UMGW 25x17x8 [M5] GW / N38 - magnetic holder internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (in laboratory conditions),
• Their ability to resist magnetic interference from external fields is among the best,
• Because of the brilliant layer of silver, the component looks visually appealing,
• Magnetic induction on the surface of these magnets is notably high,
• Thanks to their exceptional temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• The ability for precise shaping and customization to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Important function in new technology industries – they find application in hard drives, rotating machines, healthcare devices and other advanced devices,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to physical collisions, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces 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,
• Magnets exposed to moisture can degrade. Therefore, for outdoor applications, we advise waterproof types made of rubber,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is not feasible,
• Possible threat linked to microscopic shards may arise, in case of ingestion, which is significant in the protection of children. Additionally, minuscule fragments from these magnets may interfere with diagnostics after being swallowed,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Maximum lifting capacity of the magnet – what it depends on?

The given holding capacity of the magnet means the highest holding force, measured in ideal 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 polished side
• 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, in descending order of importance:

• 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.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under shearing force the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.