MW 8x1.5 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their superior power, neodymium magnets have these key benefits:

• They retain their magnetic properties for nearly ten years – the loss is just ~1% (according to analyses),
• They protect against demagnetization induced by surrounding magnetic influence effectively,
• The use of a decorative silver surface provides a refined finish,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• With the right combination of materials, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the design),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which broadens their functional possibilities,
• Key role in new technology industries – they are used in HDDs, electromechanical systems, medical equipment and sophisticated instruments,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to shocks, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from damage and strengthens its overall resistance,
• They lose strength at increased 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,
• They rust in a damp environment, especially when used outside, we recommend using encapsulated magnets, such as those made of plastic,
• Limited ability to create internal holes in the magnet – the use of a external casing is recommended,
• Safety concern related to magnet particles may arise, if ingested accidentally, which is important in the context of child safety. Moreover, tiny components from these products may interfere with diagnostics if inside the body,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum holding power of the magnet – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, determined in ideal conditions, that is:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• under perpendicular detachment force
• under standard ambient temperature

What influences lifting capacity in practice

The lifting capacity of a magnet is determined by in practice key elements, from primary to secondary:

• 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.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, however under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.