MP 12x5x2 / N38 - ring magnet

Advantages as well as disadvantages of NdFeB magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
• They have excellent resistance to weakening of magnetic properties as a result of opposing magnetic fields,
• Thanks to the smooth finish, the layer of nickel, gold-plated, or silver-plated gives an modern appearance,
• The surface of neodymium magnets generates a intense magnetic field – this is one of their assets,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Due to the possibility of free forming and customization to unique requirements, magnetic components can be modeled in a broad palette of shapes and sizes, which expands the range of possible applications,
• Key role in innovative solutions – they are commonly used in magnetic memories, electric motors, precision medical tools, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which allows their use in small systems

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• They oxidize in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We suggest a housing - magnetic mechanism, due to difficulties in producing threads inside the magnet and complicated forms.
• Potential hazard resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these devices can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

The specified lifting capacity represents the limit force, recorded under laboratory conditions, specifically:

• with the contact of a sheet made of low-carbon steel, ensuring maximum field concentration
• whose thickness reaches at least 10 mm
• with an ideally smooth contact surface
• without any clearance between the magnet and steel
• under axial force direction (90-degree angle)
• in stable room temperature

Key elements affecting lifting force

Bear in mind that the working load will differ subject to elements below, starting with the most relevant:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick steel causes magnetic saturation, causing part of the flux to be wasted to the other side.
• Material composition – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Smoothness – ideal contact is possible only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.