UMGGZ 22x6 [M4] GZ / N38 - rubber magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their magnetic field remains stable, and after around ten years, it drops only by ~1% (according to research),
• They remain magnetized despite exposure to magnetic noise,
• The use of a polished silver surface provides a refined finish,
• Magnetic induction on the surface of these magnets is notably high,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• With the option for fine forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
• Significant impact in new technology industries – they are utilized in HDDs, electric motors, diagnostic apparatus as well as sophisticated instruments,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, with minimal size,

Disadvantages of rare earth magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to external force, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage while also increases its overall durability,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent deterioration 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,
• Magnets exposed to humidity can corrode. Therefore, for outdoor applications, we advise waterproof types made of coated materials,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is restricted,
• Health risk due to small fragments may arise, if ingested accidentally, which is crucial in the family environments. Additionally, tiny components from these products might complicate medical imaging after being swallowed,
• In cases of tight budgets, neodymium magnet cost may not be economically viable,

Optimal lifting capacity of a neodymium magnet – what it depends on?

The given strength of the magnet means the optimal strength, calculated under optimal conditions, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• under perpendicular detachment force
• under standard ambient temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet is determined by in practice the following factors, according to their importance:

• Air gap between the magnet and the plate, because 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 testing was performed on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.