MPL 40x10x5x2[7/3.5] / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their exceptional field intensity, neodymium magnets offer the following advantages:

• They retain their attractive force for around ten years – the loss is just ~1% (according to analyses),
• They protect against demagnetization induced by ambient magnetic fields effectively,
• In other words, due to the metallic silver coating, the magnet obtains an aesthetic appearance,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• 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 shape),
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in diverse shapes and sizes, which increases their usage potential,
• Significant impact in cutting-edge sectors – they serve a purpose in computer drives, electromechanical systems, diagnostic apparatus and technologically developed systems,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of neodymium magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to physical collisions, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time strengthens its overall strength,
• They lose strength at extreme temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to damp air can corrode. Therefore, for outdoor applications, we suggest 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,
• Possible threat due to small fragments may arise, when consumed by mistake, which is important in the protection of children. Moreover, small elements from these products may hinder health screening if inside the body,
• In cases of mass production, neodymium magnet cost may be a barrier,

Best holding force of the magnet in ideal parameters – what it depends on?

The given strength of the magnet means the optimal strength, assessed in the best circumstances, that is:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• at room temperature

Determinants of practical lifting force of a magnet

Practical lifting force is determined by elements, by priority:

• Air gap between the magnet and the plate, as 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 checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet and the plate reduces the holding force.