UMP 135x40 [M10+M12] GW F 600 kg / N38 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their immense pulling force, neodymium magnets offer the following advantages:

• They retain their magnetic properties for almost 10 years – the loss is just ~1% (in theory),
• They protect against demagnetization induced by surrounding electromagnetic environments remarkably well,
• The use of a polished silver surface provides a eye-catching finish,
• They possess significant magnetic force measurable at the magnet’s surface,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• With the option for customized forming and precise design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Significant impact in new technology industries – they are utilized in computer drives, electric drives, clinical machines along with other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They may fracture when subjected to a sudden impact. If the magnets are exposed to external force, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks and additionally increases its overall robustness,
• They lose power at elevated temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the form 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 recommended to use sealed magnets made of rubber for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing holes directly in the magnet,
• Health risk due to small fragments may arise, especially if swallowed, which is significant in the protection of children. Furthermore, minuscule fragments from these magnets may interfere with diagnostics once in the system,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum holding power of the magnet – what affects it?

The given pulling force of the magnet means the maximum force, measured under optimal conditions, namely:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• with vertical force applied
• at room temperature

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is affected by the following aspects, in descending order of importance:

• 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 conducted on a smooth plate of optimal thickness, under perpendicular forces, in contrast under shearing force the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.