SM 32x300 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after 10 years, the decline in efficiency is only ~1% (based on calculations),
• Their ability to resist magnetic interference from external fields is notable,
• By applying a shiny layer of silver, the element gains a clean look,
• They exhibit extremely high levels of magnetic induction near the outer area 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 magnetic form),
• The ability for custom shaping and adjustment to specific needs – neodymium magnets can be manufactured in many forms and dimensions, which amplifies their functionality across industries,
• Important function in new technology industries – they are utilized in data storage devices, electromechanical systems, healthcare devices or even sophisticated instruments,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to mechanical hits, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture while also enhances its overall strength,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on size). 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,
• They rust in a humid environment. If exposed to rain, we recommend using waterproof magnets, such as those made of plastic,
• Limited ability to create internal holes in the magnet – the use of a external casing is recommended,
• Potential hazard due to small fragments may arise, if ingested accidentally, which is important in the context of child safety. Furthermore, small elements from these assemblies have the potential to complicate medical imaging when ingested,
• Due to a complex production process, their cost is relatively high,

Highest magnetic holding force – what contributes to it?

The given holding capacity of the magnet represents the highest holding force, calculated in ideal conditions, that is:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in real conditions – factors

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• Air gap between the magnet and the plate, since 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 performed on plates with a smooth surface of optimal thickness, under perpendicular forces, however under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate decreases the lifting capacity.