UMGZ 42x20x9 [M8] GZ / N38 - magnetic holder external thread

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for nearly 10 years – the loss is just ~1% (according to analyses),
• Their ability to resist magnetic interference from external fields is notable,
• In other words, due to the glossy nickel coating, the magnet obtains an aesthetic appearance,
• They possess strong magnetic force measurable at the magnet’s surface,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in various configurations, which increases their usage potential,
• Important function in new technology industries – they are used in hard drives, rotating machines, medical equipment as well as other advanced devices,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, in miniature format,

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to external force, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks and enhances its overall strength,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of synthetic coating for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing threads directly in the magnet,
• Potential hazard from tiny pieces may arise, in case of ingestion, which is important in the protection of children. Furthermore, minuscule fragments from these products can hinder health screening once in the system,
• Due to a complex production process, their cost is considerably higher,

Maximum holding power of the magnet – what affects it?

The given lifting capacity of the magnet means the maximum lifting force, measured in ideal conditions, that is:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with no separation
• in a perpendicular direction of force
• under standard ambient temperature

What influences lifting capacity in practice

The lifting capacity of a magnet is determined by in practice key elements, ordered from most important to least 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.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the lifting capacity.