MPL 3x3x3 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose their even over nearly ten years – the decrease of power is only ~1% (according to tests),
• Their ability to resist magnetic interference from external fields is impressive,
• The use of a mirror-like nickel surface provides a refined finish,
• They possess significant 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 precise shaping or customization to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
• Wide application in advanced technical fields – they are utilized in HDDs, electric drives, medical equipment and high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in compact dimensions, which makes them useful in compact constructions

Disadvantages of magnetic elements:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from damage while also reinforces its overall robustness,
• They lose strength at increased temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the dimensions 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, especially when used outside, we recommend using waterproof 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 not feasible,
• Health risk from tiny pieces may arise, when consumed by mistake, which is crucial in the family environments. Additionally, minuscule fragments from these products have the potential to disrupt scanning when ingested,
• Due to a complex production process, their cost is relatively high,

Optimal lifting capacity of a neodymium magnet – what affects it?

The given holding capacity of the magnet represents the highest holding force, calculated in ideal conditions, that is:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a smooth surface
• with no separation
• with vertical force applied
• at room temperature

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is conditioned by the following aspects, from crucial to less important:

• 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.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate reduces the holding force.