SMZR 32x150 / N52 - magnetic separator with handle

Advantages and disadvantages of rare earth magnets.

Apart from their strong power, neodymium magnets have these key benefits:

• They have constant strength, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under strong external field,
• A magnet with a metallic gold surface is more attractive,
• Neodymium magnets achieve maximum magnetic induction on a their surface, which increases force concentration,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of exact forming as well as adjusting to specific requirements,
• Versatile presence in high-tech industry – they are commonly used in mass storage devices, drive modules, precision medical tools, as well as modern systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in compact constructions

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• Limited ability of creating threads in the magnet and complex shapes - recommended is a housing - magnetic holder.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets are able to be problematic in diagnostics medical after entering the body.
• Due to complex production process, their price is relatively high,

Maximum lifting capacity of the magnet – what affects it?

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

• on a block made of structural steel, perfectly concentrating the magnetic field
• whose thickness is min. 10 mm
• with a surface free of scratches
• under conditions of ideal adhesion (metal-to-metal)
• for force applied at a right angle (in the magnet axis)
• at temperature room level

What influences lifting capacity in practice

Effective lifting capacity is influenced by specific conditions, including (from priority):

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Angle of force application – maximum parameter is obtained only during pulling at a 90° angle. The shear force of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Plate material – mild steel attracts best. Higher carbon content lower magnetic permeability and lifting capacity.
• Smoothness – ideal contact is obtained only on polished steel. Rough texture create air cushions, reducing force.
• Temperature influence – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.