FM Ruszt magnetyczny do leja fi 200 dwupoziomowy / N52 - magnetic filter

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their full power for around 10 years – the drop is just ~1% (based on simulations),
• Their ability to resist magnetic interference from external fields is impressive,
• By applying a bright layer of gold, the element gains a clean look,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to build),
• With the option for tailored forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Important function in advanced technical fields – they are utilized in computer drives, electric motors, clinical machines and sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in small dimensions, which makes them useful in compact constructions

Disadvantages of NdFeB magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to shocks, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage while also reinforces its overall durability,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent deterioration 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 advisable to use sealed magnets made of synthetic coating for outdoor use,
• Limited ability to create internal holes in the magnet – the use of a mechanical support is recommended,
• Potential hazard due to small fragments may arise, when consumed by mistake, which is crucial in the family environments. Moreover, minuscule fragments from these assemblies may interfere with diagnostics if inside the body,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Best holding force of the magnet in ideal parameters – what contributes to it?

The given lifting capacity of the magnet means the maximum lifting force, calculated under optimal conditions, that is:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with zero air gap
• with vertical force applied
• in normal thermal conditions

What influences lifting capacity in practice

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

• 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.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.