MW 6x2 / N38 - cylindrical magnet

Advantages as well as disadvantages of rare earth magnets.

Apart from their superior magnetism, neodymium magnets have these key benefits:

• They retain magnetic properties for almost 10 years – the drop is just ~1% (in theory),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• A magnet with a smooth silver surface has better aesthetics,
• Magnetic induction on the surface of the magnet turns out to be extremely intense,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of exact machining as well as adapting to atypical conditions,
• Huge importance in advanced technology sectors – they are commonly used in hard drives, electromotive mechanisms, diagnostic systems, also other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also increases their durability
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complex forms in magnets, we recommend using casing - magnetic holder.
• Possible danger to health – tiny shards of magnets are risky, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small components of these magnets can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Magnetic strength at its maximum – what it depends on?

Breakaway force was determined for the most favorable conditions, assuming:

• with the contact of a sheet made of special test steel, guaranteeing full magnetic saturation
• whose transverse dimension reaches at least 10 mm
• with an ideally smooth touching surface
• with total lack of distance (without paint)
• during pulling in a direction perpendicular to the plane
• in stable room temperature

Lifting capacity in practice – influencing factors

During everyday use, the actual lifting capacity is determined by many variables, presented from most significant:

• Gap (between the magnet and the metal), because even a very small clearance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to varnish, rust or dirt).
• Direction of force – highest force is obtained only during pulling at a 90° angle. The shear force of the magnet along the surface is standardly many times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material composition – not every steel reacts the same. Alloy additives worsen the attraction effect.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature influence – hot environment reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.