MPL 40x20x10 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after ten years, the performance loss is only ~1% (based on calculations),
• Their ability to resist magnetic interference from external fields is notable,
• Because of the lustrous layer of silver, the component looks aesthetically refined,
• They have extremely strong magnetic induction on the surface of the magnet,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• The ability for precise shaping or adaptation to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Wide application in modern technologies – they are used in data storage devices, electric motors, diagnostic apparatus and other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which makes them ideal in compact constructions

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to external force, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from damage and additionally strengthens its overall resistance,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent decline in performance (depending on height). 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 – during outdoor use, we recommend using waterproof magnets, such as those made of polymer,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is risky,
• Safety concern related to magnet particles may arise, in case of ingestion, which is crucial in the health of young users. It should also be noted that minuscule fragments from these products may interfere with diagnostics once in the system,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting capacity of the magnet – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, determined in ideal conditions, specifically:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• under perpendicular detachment force
• in normal thermal conditions

Practical aspects of lifting capacity – factors

Practical lifting force is dependent on elements, by priority:

• 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 a smooth plate of suitable thickness, under a perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.