MPL 50x20x5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their exceptional magnetic power, neodymium magnets offer the following advantages:

• They have stable power, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They show superior resistance to demagnetization from outside magnetic sources,
• By applying a shiny layer of nickel, the element gains a sleek look,
• They possess intense magnetic force measurable at the magnet’s surface,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for custom shaping or adaptation to specific needs – neodymium magnets can be manufactured in many forms and dimensions, which amplifies their functionality across industries,
• Significant impact in cutting-edge sectors – they are used in computer drives, electric drives, healthcare devices and other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in tiny dimensions, which allows for use in small systems

Disadvantages of neodymium magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to physical collisions, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and additionally enhances its overall durability,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on height). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Due to corrosion risk in humid conditions, it is common to use sealed magnets made of protective material for outdoor use,
• Limited ability to create precision features in the magnet – the use of a housing is recommended,
• Possible threat due to small fragments may arise, in case of ingestion, which is significant in the protection of children. Moreover, small elements from these assemblies might complicate medical imaging after being swallowed,
• Due to expensive raw materials, their cost is considerably higher,

Magnetic strength at its maximum – what contributes to it?

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

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Determinants of practical lifting force of a magnet

Practical lifting force is determined by factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because 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 was determined using a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate decreases the holding force.