MPL 50x50x10 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Besides their durability, neodymium magnets are valued for these benefits:

• Their strength is durable, and after approximately ten years, it drops only by ~1% (according to research),
• Their ability to resist magnetic interference from external fields is among the best,
• By applying a bright layer of silver, the element gains a clean look,
• They possess strong magnetic force measurable at the magnet’s surface,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• With the option for fine forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Significant impact in cutting-edge sectors – they are used in HDDs, electromechanical systems, medical equipment and high-tech tools,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to mechanical hits, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from cracks while also enhances its overall resistance,
• They lose magnetic force at high temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to wet conditions can corrode. Therefore, for outdoor applications, we recommend waterproof types made of coated materials,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing fine shapes directly in the magnet,
• Potential hazard linked to microscopic shards may arise, if ingested accidentally, which is important in the context of child safety. It should also be noted that miniature parts from these devices may complicate medical imaging when ingested,
• In cases of large-volume purchasing, neodymium magnet cost may not be economically viable,

Breakaway strength of the magnet in ideal conditions – 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 polished side
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Determinants of lifting force in real conditions

The lifting capacity of a magnet is determined by in practice key elements, according to their importance:

• Air gap between the magnet and the plate, because 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 performed on a smooth plate of suitable thickness, under perpendicular forces, however under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the holding force.