MW 6x2 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their durability, neodymium magnets are valued for these benefits:

• They have stable power, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by ambient magnetic fields very well,
• By applying a bright layer of gold, the element gains a modern look,
• Magnetic induction on the surface of these magnets is impressively powerful,
• 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 accurate shaping as well as adaptation to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which amplifies their functionality across industries,
• Important function in cutting-edge sectors – they are utilized in computer drives, electric motors, diagnostic apparatus or even sophisticated instruments,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, in miniature format,

Disadvantages of rare earth magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to shocks, they should be placed in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time enhances its overall strength,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on height). 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, especially when used outside, we recommend using waterproof magnets, such as those made of plastic,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is not feasible,
• Safety concern related to magnet particles may arise, especially if swallowed, which is notable in the context of child safety. It should also be noted that miniature parts from these magnets have the potential to disrupt scanning once in the system,
• Due to a complex production process, their cost is relatively high,

Maximum magnetic pulling force – what contributes to it?

The given strength of the magnet means the optimal strength, determined in the best circumstances, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a smooth surface
• with no separation
• under perpendicular detachment force
• in normal thermal conditions

Key elements affecting lifting force

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

• 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the holding force.