AM klisza magnetyczna 50 x 50 mm - magnetic accessories

Advantages and disadvantages of neodymium magnets NdFeB.

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

• Their magnetic field is durable, and after around ten years, it drops only by ~1% (theoretically),
• They remain magnetized despite exposure to magnetic noise,
• Thanks to the glossy finish and silver coating, they have an elegant appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• 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 customized forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
• Significant impact in cutting-edge sectors – they are utilized in computer drives, rotating machines, diagnostic apparatus or even sophisticated instruments,
• Thanks to their power density, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of magnetic elements:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to mechanical hits, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture and increases its overall robustness,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on form). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Due to corrosion risk in humid conditions, it is common to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing threads directly in the magnet,
• Potential hazard from tiny pieces may arise, when consumed by mistake, which is important in the family environments. It should also be noted that tiny components from these assemblies may hinder health screening if inside the body,
• Due to the price of neodymium, their cost is above average,

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

The given holding capacity of the magnet represents the highest holding force, measured in the best circumstances, 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
• under standard ambient temperature

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is conditioned by these factors, in descending order of importance:

• Air gap between the magnet and the plate, as 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 carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.