UMP 75x25 [M10x3] GW F200 GOLD DUAL Lina / N42 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after ten years, the decline in efficiency is only ~1% (in laboratory conditions),
• They are highly resistant to demagnetization caused by external magnetic sources,
• Thanks to the shiny finish and nickel coating, they have an visually attractive appearance,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• With the right combination of magnetic alloys, they reach significant thermal stability, enabling operation at or above 230°C (depending on the form),
• Thanks to the flexibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in various configurations, which expands their functional possibilities,
• Significant impact in modern technologies – they serve a purpose in computer drives, rotating machines, healthcare devices and technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in small systems

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to external force, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage and additionally reinforces its overall durability,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on height). 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 protective material for outdoor use,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is difficult,
• Possible threat due to small fragments may arise, in case of ingestion, which is important in the health of young users. Additionally, minuscule fragments from these devices have the potential to complicate medical imaging when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Magnetic strength at its maximum – what affects it?

The given pulling force of the magnet means the maximum force, calculated in the best circumstances, that is:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is conditioned by the following aspects, from crucial to less important:

• 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.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the lifting capacity.