UMGGZ 66x8.5 [M8] GZ / N38 - rubber magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years, the performance loss is only ~1% (in laboratory conditions),
• They are highly resistant to demagnetization caused by external magnetic sources,
• Because of the lustrous layer of nickel, the component looks visually appealing,
• They have extremely strong 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),
• With the option for fine forming and targeted design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Wide application in modern technologies – they serve a purpose in HDDs, electric motors, healthcare devices or even high-tech tools,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, in miniature format,

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to physical collisions, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall resistance,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to moisture can corrode. Therefore, for outdoor applications, it's best to use waterproof types made of rubber,
• Limited ability to create complex details in the magnet – the use of a external casing is recommended,
• Potential hazard linked to microscopic shards may arise, especially if swallowed, which is important in the context of child safety. Furthermore, small elements from these assemblies have the potential to disrupt scanning after being swallowed,
• Due to a complex production process, their cost is considerably higher,

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The given strength of the magnet corresponds to the optimal strength, determined in ideal conditions, namely:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• with vertical force applied
• at room temperature

Determinants of practical lifting force of a magnet

Practical lifting force is dependent on factors, by priority:

• Air gap between the magnet and the plate, because 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 testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, whereas under parallel forces the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.