MPL 25x10x3 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• Their magnetic field is maintained, and after around 10 years, it drops only by ~1% (according to research),
• They show exceptional resistance to demagnetization from external magnetic fields,
• In other words, due to the shiny silver coating, the magnet obtains an professional appearance,
• The outer field strength of the magnet shows advanced magnetic properties,
• Thanks to their high temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
• With the option for fine forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving application potential,
• Key role in advanced technical fields – they are utilized in computer drives, electric motors, clinical machines and 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 mechanical hits, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks and enhances its overall durability,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can rust. Therefore, for outdoor applications, we advise waterproof types made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing threads directly in the magnet,
• Possible threat related to magnet particles may arise, when consumed by mistake, which is crucial in the family environments. Moreover, miniature parts from these devices can disrupt scanning when ingested,
• In cases of tight budgets, neodymium magnet cost may not be economically viable,

Optimal lifting capacity of a neodymium magnet – what affects it?

The given strength of the magnet means the optimal strength, determined under optimal conditions, that is:

• with the use of low-carbon steel plate acting as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a polished side
• with no separation
• in a perpendicular direction of force
• under standard ambient temperature

Magnet lifting force in use – key factors

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• Air gap between the magnet and the plate, as 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.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the load capacity is reduced by as much as 75%. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.