UMH 48x11x65 [M6] / N38 - magnetic holder with hook

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have unchanged lifting capacity, and over nearly 10 years their performance decreases symbolically – ~1% (according to theory),
• They remain magnetized despite exposure to strong external fields,
• Thanks to the polished finish and gold coating, they have an aesthetic appearance,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• Thanks to their enhanced temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• With the option for fine forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving design adaptation,
• Key role in advanced technical fields – they find application in computer drives, rotating machines, diagnostic apparatus or even technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile 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 breakage while also increases its overall robustness,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent decline 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 synthetic coating for outdoor use,
• Limited ability to create internal holes in the magnet – the use of a mechanical support is recommended,
• Potential hazard linked to microscopic shards may arise, in case of ingestion, which is crucial in the family environments. Additionally, small elements from these devices have the potential to complicate medical imaging once in the system,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting capacity of the magnet – what it depends on?

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

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet is determined by in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, since 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 was determined using a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.