SM 32x475 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain their attractive force for nearly ten years – the drop is just ~1% (according to analyses),
• They remain magnetized despite exposure to magnetic surroundings,
• In other words, due to the glossy gold coating, the magnet obtains an professional appearance,
• They possess intense magnetic force measurable at the magnet’s surface,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to form),
• The ability for accurate shaping and customization to individual needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Significant impact in new technology industries – they are utilized in HDDs, electric drives, medical equipment and technologically developed systems,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to mechanical hits, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture while also increases its overall durability,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on form). 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,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we advise waterproof types made of coated materials,
• Limited ability to create internal holes in the magnet – the use of a magnetic holder is recommended,
• Safety concern due to small fragments may arise, if ingested accidentally, which is significant in the context of child safety. Furthermore, minuscule fragments from these products have the potential to disrupt scanning after being swallowed,
• In cases of large-volume purchasing, neodymium magnet cost is a challenge,

Maximum lifting capacity of the magnet – what affects it?

The given strength of the magnet represents the optimal strength, measured in the best circumstances, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• with vertical force applied
• under standard ambient temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice key elements, ordered from most important to least significant:

• Air gap between the magnet and the plate, because 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 performed on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.