MPL 200x30x30 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (in laboratory conditions),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the lustrous layer of gold, the component looks aesthetically refined,
• The outer field strength of the magnet shows elevated magnetic properties,
• With the right combination of compounds, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the design),
• With the option for fine forming and targeted design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Important function in cutting-edge sectors – they are utilized in computer drives, electromechanical systems, clinical machines or even other advanced devices,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of magnetic elements:

• They can break when subjected to a strong impact. If the magnets are exposed to physical collisions, they should be placed in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture and additionally reinforces its overall strength,
• They lose field intensity at elevated temperatures. Most neodymium magnets experience permanent decline 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,
• They rust in a humid environment. If exposed to rain, we recommend using sealed magnets, such as those made of plastic,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is not feasible,
• Safety concern from tiny pieces may arise, if ingested accidentally, which is important in the health of young users. Additionally, tiny components from these magnets have the potential to interfere with diagnostics when ingested,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Maximum lifting force for a neodymium magnet – what it depends on?

The given lifting capacity of the magnet corresponds to the maximum lifting force, measured in the best circumstances, that is:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• in a perpendicular direction of force
• at room temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet depends on in practice key elements, ordered from most important to least significant:

• Air gap between the magnet and the plate, as 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 measured with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the load capacity.