MW 10x4 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (according to literature),
• Neodymium magnets are distinguished by remarkably resistant to demagnetization caused by magnetic disturbances,
• By covering with a decorative coating of gold, the element presents an elegant look,
• The surface of neodymium magnets generates a concentrated magnetic field – this is one of their assets,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures approaching 230°C and above...
• Thanks to freedom in designing and the ability to customize to individual projects,
• Universal use in electronics industry – they find application in mass storage devices, electric motors, medical equipment, as well as multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited ability of creating nuts in the magnet and complex shapes - preferred is cover - magnet mounting.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child health protection. It is also worth noting that small components of these magnets can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Magnetic strength at its maximum – what contributes to it?

Breakaway force was defined for ideal contact conditions, including:

• using a plate made of high-permeability steel, serving as a circuit closing element
• possessing a thickness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• with total lack of distance (no impurities)
• for force applied at a right angle (in the magnet axis)
• at temperature room level

Magnet lifting force in use – key factors

In real-world applications, the real power is determined by several key aspects, ranked from crucial:

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick plate causes magnetic saturation, causing part of the power to be escaped into the air.
• Material composition – different alloys reacts the same. Alloy additives worsen the attraction effect.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.