MPL 200x30x30 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their immense magnetic power, neodymium magnets offer the following advantages:

• They do not lose their even during approximately ten years – the reduction of strength is only ~1% (theoretically),
• They remain magnetized despite exposure to magnetic noise,
• In other words, due to the shiny silver coating, the magnet obtains an professional appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• Thanks to their high temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in various configurations, which increases their functional possibilities,
• Significant impact in new technology industries – they serve a purpose in hard drives, electric drives, medical equipment as well as other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which makes them useful in compact constructions

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is suggested to place them in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture and additionally reinforces its overall strength,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to humidity can oxidize. Therefore, for outdoor applications, it's best to use waterproof types made of non-metallic composites,
• Limited ability to create complex details in the magnet – the use of a housing is recommended,
• Potential hazard due to small fragments may arise, if ingested accidentally, which is significant in the protection of children. Moreover, tiny components from these magnets might interfere with diagnostics if inside the body,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The given pulling force of the magnet corresponds to the maximum force, calculated in the best circumstances, namely:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• with zero air gap
• with vertical force applied
• under standard ambient temperature

Practical aspects of lifting capacity – factors

In practice, the holding capacity of a magnet is affected by these factors, in descending order of importance:

• 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 conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.