MW 6x2 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is maintained, and after around 10 years, it drops only by ~1% (according to research),
• They protect against demagnetization induced by surrounding magnetic fields very well,
• The use of a decorative nickel surface provides a eye-catching finish,
• They have very high 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 geometry),
• The ability for custom shaping as well as adjustment to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Significant impact in cutting-edge sectors – they find application in computer drives, electric drives, healthcare devices as well as technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture while also reinforces its overall resistance,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a moist environment – during outdoor use, we recommend using sealed magnets, such as those made of non-metallic materials,
• Limited ability to create complex details in the magnet – the use of a mechanical support is recommended,
• Possible threat linked to microscopic shards may arise, in case of ingestion, which is significant in the health of young users. Furthermore, tiny components from these devices have the potential to hinder health screening if inside the body,
• In cases of mass production, neodymium magnet cost is a challenge,

Maximum holding power of the magnet – what it depends on?

The given lifting capacity of the magnet represents the maximum lifting force, calculated in a perfect environment, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a polished side
• with no separation
• with vertical force applied
• under standard ambient temperature

Practical aspects of lifting capacity – factors

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

• 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 testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.