UMGZ 16x13x5 [M4] GZ / N38 - magnetic holder external thread

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their notable magnetism, neodymium magnets have these key benefits:

• They do not lose their magnetism, even after around ten years – the reduction of lifting capacity is only ~1% (according to tests),
• They remain magnetized despite exposure to magnetic noise,
• Thanks to the polished finish and nickel coating, they have an aesthetic appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• The ability for accurate shaping and customization to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which extends the scope of their use cases,
• Key role in new technology industries – they find application in computer drives, rotating machines, clinical machines along with sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in tiny dimensions, which makes them ideal in small systems

Disadvantages of magnetic elements:

• They can break when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture and strengthens its overall robustness,
• High temperatures may significantly reduce the field efficiency 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,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of synthetic coating for outdoor use,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Health risk from tiny pieces may arise, if ingested accidentally, which is notable in the context of child safety. It should also be noted that minuscule fragments from these products may complicate medical imaging once in the system,
• In cases of tight budgets, neodymium magnet cost may not be economically viable,

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

The given lifting capacity of the magnet corresponds to the maximum lifting force, calculated under optimal conditions, that is:

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a polished side
• in conditions of no clearance
• in a perpendicular direction of force
• in normal thermal conditions

Magnet lifting force in use – key factors

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 with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the load capacity is reduced by as much as 75%. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.