MW 5x15 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets.

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

• They retain magnetic properties for nearly 10 years – the drop is just ~1% (in theory),
• Neodymium magnets remain remarkably resistant to magnetic field loss caused by external field sources,
• In other words, due to the shiny layer of silver, the element gains visual value,
• 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, allowing for action at temperatures reaching 230°C and above...
• Possibility of detailed shaping and modifying to individual conditions,
• Universal use in electronics industry – they are used in hard drives, electric drive systems, diagnostic systems, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which allows their use in small systems

Characteristics of disadvantages of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce 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 suggest using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets are risky, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that tiny parts of these devices are able to complicate diagnosis medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum holding power of the magnet – what it depends on?

Information about lifting capacity is the result of a measurement for ideal contact conditions, assuming:

• on a base made of structural steel, effectively closing the magnetic field
• whose thickness is min. 10 mm
• with an polished contact surface
• with total lack of distance (without impurities)
• for force applied at a right angle (pull-off, not shear)
• in stable room temperature

Determinants of lifting force in real conditions

Real force is influenced by specific conditions, mainly (from most important):

• Distance – the presence of foreign body (paint, dirt, air) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick plate causes magnetic saturation, causing part of the power to be lost into the air.
• Material composition – different alloys reacts the same. High carbon content weaken the attraction effect.
• Surface finish – ideal contact is obtained only on smooth steel. Rough texture reduce the real contact area, reducing force.
• Thermal factor – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.