UMP 94x28 [3xM10] GW F300 GOLD / N38 - search holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for nearly ten years – the drop is just ~1% (in theory),
• They remain magnetized despite exposure to magnetic noise,
• The use of a mirror-like gold surface provides a eye-catching finish,
• They have exceptional magnetic induction on the surface of the magnet,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• With the option for customized forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Important function in new technology industries – they serve a purpose in data storage devices, electric motors, medical equipment and technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them ideal in compact constructions

Disadvantages of neodymium magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to mechanical hits, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time reinforces its overall strength,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent decline in performance (depending on shape). 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 damp environment. If exposed to rain, we recommend using encapsulated magnets, such as those made of polymer,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing complex structures directly in the magnet,
• Possible threat related to magnet particles may arise, when consumed by mistake, which is important in the context of child safety. Furthermore, miniature parts from these products may disrupt scanning after being swallowed,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Highest magnetic holding force – what affects it?

The given lifting capacity of the magnet means the maximum lifting force, determined in a perfect environment, that is:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• with vertical force applied
• at room temperature

What influences lifting capacity in practice

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• 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.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.