UMGZ 48x24x11.5 [M8] GZ / N38 - magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• They retain full power for around ten years – the drop is just ~1% (in theory),
• They feature excellent resistance to weakening of magnetic properties when exposed to external magnetic sources,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• They feature high magnetic induction at the operating surface, which increases their power,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of individual shaping and modifying to precise conditions,
• Versatile presence in electronics industry – they are utilized in HDD drives, drive modules, diagnostic systems, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a strong case, which not only secures them against impacts but also raises their durability
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation as well as corrosion.
• Limited possibility of creating threads in the magnet and complex shapes - recommended is casing - magnetic holder.
• Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what contributes to it?

Information about lifting capacity is the result of a measurement for optimal configuration, including:

• using a plate made of high-permeability steel, functioning as a circuit closing element
• whose transverse dimension is min. 10 mm
• characterized by even structure
• without any clearance between the magnet and steel
• during pulling in a direction vertical to the plane
• in neutral thermal conditions

Practical lifting capacity: influencing factors

In practice, the real power depends on a number of factors, ranked from the most important:

• Clearance – existence of any layer (paint, dirt, gap) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Steel thickness – too thin steel does not accept the full field, causing part of the flux to be escaped to the other side.
• Metal type – not every steel attracts identically. Alloy additives worsen the attraction effect.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Temperature – heating the magnet causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.