SMZR 32x150 / N52 - magnetic separator with handle

Advantages and disadvantages of neodymium magnets NdFeB.

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

• Their magnetic field is maintained, and after approximately 10 years, it drops only by ~1% (according to research),
• They are highly resistant to demagnetization caused by external field interference,
• By applying a reflective layer of silver, the element gains a modern look,
• They have extremely strong magnetic induction on the surface of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for accurate shaping and adaptation to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Wide application in advanced technical fields – they are used in data storage devices, electric drives, healthcare devices and sophisticated instruments,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to mechanical hits, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and additionally strengthens its overall robustness,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a damp environment. If exposed to rain, we recommend using waterproof magnets, such as those made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing fine shapes directly in the magnet,
• Potential hazard from tiny pieces may arise, if ingested accidentally, which is important in the health of young users. Additionally, miniature parts from these assemblies might interfere with diagnostics after being swallowed,
• In cases of large-volume purchasing, neodymium magnet cost may not be economically viable,

Maximum lifting force for a neodymium magnet – what affects it?

The given holding capacity of the magnet represents the highest holding force, calculated under optimal conditions, specifically:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• under perpendicular detachment force
• at room temperature

Lifting capacity in real conditions – factors

Practical lifting force is determined by 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate lowers the load capacity.