MPL 40x18x10 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• Their magnetic field remains stable, and after approximately ten years, it drops only by ~1% (theoretically),
• They show superior resistance to demagnetization from outside magnetic sources,
• Because of the reflective layer of silver, the component looks high-end,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• Thanks to their high temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• With the option for customized forming and targeted design, these magnets can be produced in multiple shapes and sizes, greatly improving engineering flexibility,
• Key role in cutting-edge sectors – they serve a purpose in data storage devices, electric drives, medical equipment as well as other advanced devices,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to shocks, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage and additionally reinforces its overall robustness,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a moist environment. For outdoor use, we recommend using sealed magnets, such as those made of polymer,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing holes directly in the magnet,
• Potential hazard related to magnet particles may arise, if ingested accidentally, which is crucial in the protection of children. Furthermore, miniature parts from these assemblies might hinder health screening after being swallowed,
• Due to expensive raw materials, their cost is above average,

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

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

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a smooth surface
• with zero air gap
• with vertical force applied
• at room temperature

Magnet lifting force in use – key factors

Practical lifting force is dependent on factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, since 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.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the lifting capacity.