UMGB 135x40 [M10+M12] GW F600 +Lina GOBLIN / N38 - goblin magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

Besides their durability, neodymium magnets are valued for these benefits:

• Their power remains stable, and after around 10 years, it drops only by ~1% (theoretically),
• Their ability to resist magnetic interference from external fields is among the best,
• Because of the brilliant layer of gold, the component looks aesthetically refined,
• They have exceptional magnetic induction on the surface of the magnet,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• The ability for custom shaping or customization to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Significant impact in advanced technical fields – they serve a purpose in hard drives, rotating machines, clinical machines and sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them ideal in miniature devices

Disadvantages of magnetic elements:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from cracks and additionally enhances its overall strength,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent weakening 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 moisture can degrade. Therefore, for outdoor applications, we advise waterproof types made of coated materials,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing fine shapes directly in the magnet,
• Health risk due to small fragments may arise, especially if swallowed, which is notable in the context of child safety. Moreover, miniature parts from these assemblies can disrupt scanning if inside the body,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Magnetic strength at its maximum – what it depends on?

The given holding capacity of the magnet corresponds to the highest holding force, assessed under optimal conditions, that is:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• under standard ambient temperature

Key elements affecting lifting force

The lifting capacity of a magnet is influenced by in practice the following factors, according to their importance:

• Air gap between the magnet and the plate, since 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 measured using a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.