UMH 16x5x32 [M4] / N38 - magnetic holder with hook

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over more than 10 years their performance decreases symbolically – ~1% (in testing),
• They remain magnetized despite exposure to magnetic noise,
• Because of the brilliant layer of nickel, the component looks aesthetically refined,
• Magnetic induction on the surface of these magnets is impressively powerful,
• With the right combination of magnetic alloys, they reach significant thermal stability, enabling operation at or above 230°C (depending on the design),
• The ability for accurate shaping and adjustment to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Significant impact in advanced technical fields – they are used in data storage devices, electromechanical systems, healthcare devices and high-tech tools,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, with minimal size,

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to external force, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time increases its overall resistance,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss 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 wet conditions can oxidize. Therefore, for outdoor applications, we suggest waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is restricted,
• Safety concern from tiny pieces may arise, when consumed by mistake, which is notable in the protection of children. It should also be noted that miniature parts from these devices can complicate medical imaging if inside the body,
• In cases of large-volume purchasing, neodymium magnet cost may be a barrier,

Maximum holding power of the magnet – what it depends on?

The given strength of the magnet corresponds to the optimal strength, measured in the best circumstances, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• in normal thermal conditions

Key elements affecting lifting force

Practical lifting force is dependent on factors, by priority:

• Air gap between the magnet and the plate, since 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.

* Lifting capacity was measured using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.