UMC 42x7/4x9 / N38 - cylindrical magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after ten years, the performance loss is only ~1% (in laboratory conditions),
• They are extremely resistant to demagnetization caused by external field interference,
• By applying a bright layer of gold, the element gains a clean look,
• They have exceptional magnetic induction on the surface of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for accurate shaping as well as adjustment to specific needs – neodymium magnets can be manufactured in many forms and dimensions, which enhances their versatility in applications,
• Significant impact in advanced technical fields – they are utilized in HDDs, electromechanical systems, medical equipment and sophisticated instruments,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture and enhances its overall resistance,
• They lose magnetic force at extreme temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is common to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing threads directly in the magnet,
• Potential hazard linked to microscopic shards may arise, if ingested accidentally, which is significant in the family environments. Moreover, small elements from these assemblies have the potential to disrupt scanning if inside the body,
• In cases of tight budgets, neodymium magnet cost may be a barrier,

Highest magnetic holding force – what affects it?

The given strength of the magnet represents the optimal strength, measured in the best circumstances, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a polished side
• with no separation
• with vertical force applied
• at room temperature

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet is determined by in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, as 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 conducted on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.