SM 32x425 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their remarkable magnetic power, neodymium magnets offer the following advantages:

• Their strength remains stable, and after around ten years, it drops only by ~1% (theoretically),
• They show superior resistance to demagnetization from external magnetic fields,
• By applying a bright layer of silver, the element gains a sleek look,
• They exhibit elevated 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),
• With the option for customized forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Significant impact in modern technologies – they serve a purpose in hard drives, electromechanical systems, medical equipment or even other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in small dimensions, which makes them ideal in small systems

Disadvantages of neodymium magnets:

• They are fragile when subjected to a strong impact. If the magnets are exposed to mechanical hits, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from fracture and increases its overall resistance,
• They lose strength at high temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the form 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. If exposed to rain, we recommend using encapsulated magnets, such as those made of polymer,
• Limited ability to create precision features in the magnet – the use of a mechanical support is recommended,
• Possible threat due to small fragments may arise, in case of ingestion, which is important in the context of child safety. Additionally, small elements from these magnets can disrupt scanning after being swallowed,
• In cases of mass production, neodymium magnet cost may not be economically viable,

Breakaway strength of the magnet in ideal conditions – what it depends on?

The given holding capacity of the magnet represents the highest holding force, measured under optimal conditions, that is:

• 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 polished side
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Key elements affecting lifting force

Practical lifting force is dependent on factors, 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 performed on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.