MPL 40x15x5x2[7/3.5] / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their superior magnetism, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years, the decline in efficiency is only ~1% (based on calculations),
• They protect against demagnetization induced by external magnetic fields very well,
• In other words, due to the metallic nickel coating, the magnet obtains an aesthetic appearance,
• Magnetic induction on the surface of these magnets is very strong,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to build),
• With the option for customized forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Significant impact in modern technologies – they find application in data storage devices, electromechanical systems, healthcare devices and high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which allows for use in compact constructions

Disadvantages of NdFeB magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to shocks, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time reinforces its overall resistance,
• They lose strength at extreme 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,
• Magnets exposed to humidity can oxidize. Therefore, for outdoor applications, we recommend waterproof types made of non-metallic composites,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Potential hazard linked to microscopic shards may arise, especially if swallowed, which is significant in the health of young users. It should also be noted that minuscule fragments from these devices have the potential to complicate medical imaging once in the system,
• Due to expensive raw materials, their cost is considerably higher,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The given pulling force of the magnet means the maximum force, calculated in the best circumstances, that is:

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

Practical aspects of lifting capacity – factors

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) 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.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.