SM 25x200 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

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

• They do not lose magnetism, even over nearly ten years – the decrease in power is only ~1% (based on measurements),
• They do not lose their magnetic properties even under close interference source,
• A magnet with a shiny silver surface looks better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• 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...
• Thanks to flexibility in forming and the ability to adapt to unusual requirements,
• Key role in advanced technology sectors – they find application in HDD drives, motor assemblies, advanced medical instruments, also multitasking production systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• At very strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets decrease 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 stability even at temperatures up to 230°C
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We suggest cover - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these products can be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum lifting capacity of the magnet – what affects it?

The specified lifting capacity concerns the peak performance, obtained under ideal test conditions, namely:

• using a plate made of high-permeability steel, serving as a ideal flux conductor
• whose transverse dimension is min. 10 mm
• characterized by smoothness
• under conditions of ideal adhesion (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Magnet lifting force in use – key factors

Real force impacted by specific conditions, such as (from priority):

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during perpendicular pulling. The force required to slide of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Cast iron may attract less.
• Surface quality – the more even the surface, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Thermal environment – temperature increase results in weakening of force. Check the maximum operating temperature for a given model.

* Lifting capacity was determined by applying a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.