MPL 5x5x2 / N38 - lamellar magnet

Advantages as well as disadvantages of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They do not lose strength, even during around ten years – the drop in lifting capacity is only ~1% (according to tests),
• They possess excellent resistance to magnetic field loss as a result of external fields,
• In other words, due to the glossy surface of silver, the element gains visual value,
• The surface of neodymium magnets generates a maximum magnetic field – this is one of their assets,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of individual creating as well as optimizing to defined needs,
• Key role in modern industrial fields – they are used in mass storage devices, electric motors, precision medical tools, and complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of making nuts in the magnet and complex shapes - preferred is a housing - magnet mounting.
• Health risk resulting from small fragments of magnets are risky, if swallowed, which gains importance in the context of child health protection. It is also worth noting that small components of these devices can be problematic in diagnostics medical when they are in the body.
• With mass production the cost of neodymium magnets is a challenge,

Maximum lifting force for a neodymium magnet – what contributes to it?

Breakaway force is the result of a measurement for ideal contact conditions, taking into account:

• on a plate made of mild steel, effectively closing the magnetic field
• possessing a thickness of min. 10 mm to avoid saturation
• characterized by smoothness
• under conditions of ideal adhesion (metal-to-metal)
• for force applied at a right angle (pull-off, not shear)
• at temperature room level

Practical aspects of lifting capacity – factors

Please note that the working load will differ influenced by elements below, in order of importance:

• Clearance – the presence of foreign body (rust, dirt, gap) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Alloy steels lower magnetic properties and lifting capacity.
• Surface quality – the more even the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature influence – high temperature weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the load capacity.