UMP 107x40 [M8+M10] GW F 400 kg / N38 - search holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their stability, neodymium magnets are valued for these benefits:

• They have constant strength, and over around 10 years their attraction force decreases symbolically – ~1% (in testing),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the lustrous layer of gold, the component looks aesthetically refined,
• The outer field strength of the magnet shows remarkable magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• With the option for fine forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
• Wide application in cutting-edge sectors – they serve a purpose in computer drives, electric drives, clinical machines as well as high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in tiny dimensions, which makes them ideal in miniature devices

Disadvantages of neodymium magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to mechanical hits, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage while also reinforces its overall durability,
• They lose magnetic force at high temperatures. Most neodymium magnets experience permanent reduction 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,
• They rust in a humid environment. If exposed to rain, we recommend using encapsulated magnets, such as those made of polymer,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is important in the health of young users. Additionally, minuscule fragments from these devices have the potential to hinder health screening when ingested,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Magnetic strength at its maximum – what contributes to it?

The given lifting capacity of the magnet means the maximum lifting force, measured in a perfect environment, namely:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Key elements affecting lifting force

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

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