SM 32x400 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They retain attractive force for nearly ten years – the drop is just ~1% (in theory),
• They show high resistance to demagnetization induced by external field influence,
• A magnet with a shiny nickel surface looks better,
• The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to flexibility in shaping and the capacity to customize to unusual requirements,
• Huge importance in innovative solutions – they find application in data components, electric motors, advanced medical instruments, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which enables their usage in compact constructions

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets decrease their power 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 while using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing threads and complex forms in magnets, we propose using a housing - magnetic mount.
• Health risk to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, tiny parts of these devices can be problematic in diagnostics medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Maximum lifting capacity of the magnet – what it depends on?

The load parameter shown represents the peak performance, obtained under ideal test conditions, meaning:

• using a plate made of low-carbon steel, acting as a circuit closing element
• with a cross-section minimum 10 mm
• with an polished contact surface
• with zero gap (no impurities)
• under perpendicular force vector (90-degree angle)
• at temperature room level

Key elements affecting lifting force

Holding efficiency is affected by specific conditions, mainly (from most important):

• Distance – existence of any layer (rust, tape, air) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Angle of force application – highest force is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Hardened steels may attract less.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Thermal factor – hot environment weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.