UMS 20x8.6x4.5x7 / N38 - conical magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (in laboratory conditions),
• They protect against demagnetization induced by ambient electromagnetic environments remarkably well,
• By applying a shiny layer of gold, the element gains a modern look,
• They possess intense magnetic force measurable at the magnet’s surface,
• With the right combination of materials, they reach significant thermal stability, enabling operation at or above 230°C (depending on the form),
• With the option for customized forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Significant impact in new technology industries – they serve a purpose in data storage devices, rotating machines, diagnostic apparatus along with other advanced devices,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They can break when subjected to a strong impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time strengthens its overall robustness,
• High temperatures may significantly reduce the field efficiency 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,
• They rust in a wet environment – during outdoor use, we recommend using encapsulated magnets, such as those made of plastic,
• Limited ability to create precision features in the magnet – the use of a external casing is recommended,
• Possible threat linked to microscopic shards may arise, in case of ingestion, which is important in the health of young users. Furthermore, tiny components from these magnets have the potential to hinder health screening after being swallowed,
• Due to a complex production process, their cost is relatively high,

Maximum magnetic pulling force – what it depends on?

The given strength of the magnet means the optimal strength, measured in the best circumstances, that is:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• 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 the plate surface of 20 mm thickness, when a perpendicular force was applied, however under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet and the plate decreases the load capacity.