UMGW 32x18x8 [M6] GW / N38 - magnetic holder internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after 10 years, the performance loss is only ~1% (in laboratory conditions),
• They protect against demagnetization induced by surrounding magnetic influence very well,
• Thanks to the glossy finish and silver coating, they have an aesthetic appearance,
• They possess significant magnetic force measurable at the magnet’s surface,
• With the right combination of compounds, they reach significant thermal stability, enabling operation at or above 230°C (depending on the design),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which expands their functional possibilities,
• Significant impact in modern technologies – they are utilized in hard drives, rotating machines, clinical machines as well as technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in tiny dimensions, which allows for use in small systems

Disadvantages of magnetic elements:

• They can break when subjected to a heavy impact. If the magnets are exposed to physical collisions, it is suggested to place them in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage and additionally reinforces its overall resistance,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent weakening 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 corrode. Therefore, for outdoor applications, we recommend waterproof types made of coated materials,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing threads directly in the magnet,
• Health risk linked to microscopic shards may arise, if ingested accidentally, which is notable in the protection of children. It should also be noted that miniature parts from these products can disrupt scanning after being swallowed,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum magnetic pulling force – what contributes to it?

The given holding capacity of the magnet means the highest holding force, measured in the best circumstances, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with no separation
• in a perpendicular direction of force
• under standard ambient temperature

Lifting capacity in real conditions – factors

Practical lifting force is determined by elements, listed from the most critical to the less significant:

• 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.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the holding force.