MW 5x15 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

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

• They have constant strength, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They are noted for resistance to demagnetization induced by external field influence,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• In view of the possibility of accurate molding and adaptation to unique solutions, magnetic components can be manufactured in a wide range of forms and dimensions, which makes them more universal,
• Key role in electronics industry – they find application in data components, motor assemblies, advanced medical instruments, and complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which allows their use in compact constructions

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only shields the magnet but also increases its resistance to damage
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing nuts and complex forms in magnets, we recommend using cover - magnetic holder.
• Potential hazard related to microscopic parts of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these products are able to complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Highest magnetic holding force – what it depends on?

Breakaway force was defined for optimal configuration, including:

• on a plate made of mild steel, effectively closing the magnetic field
• whose transverse dimension equals approx. 10 mm
• with a surface cleaned and smooth
• under conditions of no distance (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• in neutral thermal conditions

Key elements affecting lifting force

In practice, the real power depends on several key aspects, presented from most significant:

• Clearance – the presence of foreign body (rust, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Steel thickness – insufficiently thick plate does not close the flux, causing part of the power to be wasted to the other side.
• Material composition – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate reduces the lifting capacity.