MW 10x10 / N38 - cylindrical magnet

Pros and cons of rare earth magnets.

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

• They retain attractive force for almost 10 years – the loss is just ~1% (in theory),
• Magnets perfectly defend themselves against loss of magnetization caused by foreign field sources,
• In other words, due to the metallic finish of silver, the element looks attractive,
• The surface of neodymium magnets generates a powerful magnetic field – this is a distinguishing feature,
• 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 option of precise forming and adaptation to custom needs, magnetic components can be created in a variety of shapes and sizes, which makes them more universal,
• Universal use in modern technologies – they find application in magnetic memories, electric motors, medical equipment, as well as multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which enables their usage in small systems

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets decrease their strength 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• We recommend a housing - magnetic holder, due to difficulties in producing nuts inside the magnet and complex shapes.
• Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. Additionally, tiny parts of these devices are able to complicate diagnosis medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

Breakaway strength of the magnet in ideal conditions – what it depends on?

Breakaway force is the result of a measurement for the most favorable conditions, including:

• using a plate made of high-permeability steel, functioning as a magnetic yoke
• whose transverse dimension is min. 10 mm
• with an ideally smooth contact surface
• under conditions of ideal adhesion (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

During everyday use, the actual holding force results from several key aspects, presented from crucial:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Plate material – low-carbon steel gives the best results. Alloy steels lower magnetic properties and holding force.
• Surface quality – the more even the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Thermal environment – heating the magnet causes a temporary drop of force. Check the thermal limit for a given model.

* Lifting capacity was measured using a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied 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 reduces the holding force.