MP 16x12x2 / N38 - ring magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their magnetic properties for almost 10 years – the loss is just ~1% (according to analyses),
• They remain magnetized despite exposure to magnetic surroundings,
• Thanks to the shiny finish and gold coating, they have an elegant appearance,
• They have very high magnetic induction on the surface of the magnet,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• The ability for precise shaping or customization to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Significant impact in cutting-edge sectors – they find application in computer drives, electric motors, clinical machines and technologically developed systems,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage and strengthens its overall robustness,
• High temperatures may significantly reduce the magnetic power 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,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is not feasible,
• Health risk from tiny pieces may arise, when consumed by mistake, which is important in the health of young users. Furthermore, miniature parts from these devices might disrupt scanning once in the system,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Optimal lifting capacity of a neodymium magnet – what it depends on?

The given holding capacity of the magnet represents the highest holding force, calculated in the best circumstances, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• 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.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as 5 times. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.