MPL 30x20x5 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose their even during around 10 years – the decrease of strength is only ~1% (based on measurements),
• They show superior resistance to demagnetization from outside magnetic sources,
• Because of the lustrous layer of silver, the component looks high-end,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• With the right combination of magnetic alloys, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• With the option for tailored forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving engineering flexibility,
• Key role in new technology industries – they find application in HDDs, rotating machines, medical equipment along with sophisticated instruments,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to mechanical hits, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall resistance,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible power drop (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing fine shapes directly in the magnet,
• Potential hazard related to magnet particles may arise, if ingested accidentally, which is important in the family environments. Moreover, minuscule fragments from these products might disrupt scanning when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Detachment force of the magnet in optimal conditions – what affects it?

The given holding capacity of the magnet corresponds to the highest holding force, assessed in the best circumstances, namely:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Practical aspects of lifting capacity – factors

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) 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 carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate decreases the load capacity.