UMGGW 22x6 [M4] GW / N38 - magnetic holder rubber internal 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% (based on calculations),
• They show strong resistance to demagnetization from external magnetic fields,
• Thanks to the polished finish and gold coating, they have an elegant appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• 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),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which expands their functional possibilities,
• Important function in cutting-edge sectors – they are used in HDDs, electric drives, medical equipment along with technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to external force, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and additionally strengthens its overall strength,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible power drop (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,
• Magnets exposed to moisture can rust. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• Limited ability to create complex details in the magnet – the use of a external casing is recommended,
• Possible threat related to magnet particles may arise, if ingested accidentally, which is notable in the health of young users. Furthermore, miniature parts from these devices might disrupt scanning when ingested,
• Due to the price of neodymium, their cost is considerably higher,

Highest magnetic holding force – what it depends on?

The given holding capacity of the magnet represents the highest holding force, determined in ideal conditions, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Practical aspects of lifting capacity – factors

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.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate lowers the lifting capacity.