MPL 30x10x5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They retain their full power for around 10 years – the drop is just ~1% (based on simulations),
• Their ability to resist magnetic interference from external fields is impressive,
• Thanks to the glossy finish and gold coating, they have an visually attractive appearance,
• The outer field strength of the magnet shows advanced magnetic properties,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which broadens their usage potential,
• Important function in modern technologies – they are utilized in data storage devices, electric motors, medical equipment and high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in compact constructions

Disadvantages of rare earth magnets:

• They are fragile when subjected to a strong 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 cracks while also enhances its overall robustness,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent deterioration 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,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of synthetic coating for outdoor use,
• Limited ability to create precision features in the magnet – the use of a mechanical support is recommended,
• Health risk related to magnet particles may arise, if ingested accidentally, which is crucial in the context of child safety. Additionally, tiny components from these products can complicate medical imaging if inside the body,
• Due to the price of neodymium, their cost is relatively high,

Maximum magnetic pulling force – what contributes to it?

The given strength of the magnet represents the optimal strength, measured under optimal conditions, namely:

• with mild steel, serving 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
• at room temperature

Practical aspects of lifting capacity – factors

Practical lifting force is dependent on factors, listed from the most critical to the less 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 carried out on a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the holding force.