MPL 30x15x2 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (in testing),
• They remain magnetized despite exposure to magnetic noise,
• Thanks to the shiny finish and nickel coating, they have an aesthetic appearance,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• 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 tailored forming and targeted design, these magnets can be produced in various shapes and sizes, greatly improving application potential,
• Key role in advanced technical fields – they find application in HDDs, electric motors, medical equipment as well as high-tech tools,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time increases its overall resistance,
• They lose power at increased temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a wet environment, especially when used outside, we recommend using encapsulated magnets, such as those made of non-metallic materials,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is restricted,
• Possible threat linked to microscopic shards may arise, when consumed by mistake, which is important in the protection of children. It should also be noted that small elements from these assemblies may interfere with diagnostics when ingested,
• In cases of large-volume purchasing, neodymium magnet cost is a challenge,

Maximum holding power of the magnet – what it depends on?

The given lifting capacity of the magnet corresponds to the maximum lifting force, calculated in ideal conditions, 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
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet depends on in practice the following factors, ordered from most important to least 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 testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling force, whereas under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet and the plate decreases the holding force.