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

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They virtually do not lose strength, because even after ten years, the decline in efficiency is only ~1% (based on calculations),
• Their ability to resist magnetic interference from external fields is among the best,
• By applying a shiny layer of nickel, the element gains a sleek look,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• With the right combination of magnetic alloys, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the structure),
• With the option for fine forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving application potential,
• Important function in cutting-edge sectors – they are utilized in data storage devices, electromechanical systems, medical equipment and other advanced devices,
• Thanks to their power density, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of NdFeB magnets:

• They can break when subjected to a powerful impact. If the magnets are exposed to external force, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture and reinforces its overall strength,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on size). 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 recommended to use sealed magnets made of rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is restricted,
• Safety concern due to small fragments may arise, in case of ingestion, which is crucial in the family environments. Moreover, tiny components from these products have the potential to complicate medical imaging if inside the body,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The given pulling force of the magnet represents the maximum force, assessed in ideal conditions, that is:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• at room temperature

Practical lifting capacity: influencing factors

Practical lifting force is determined by 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) 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 assessed using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate decreases the holding force.