SM 32x425 [2xM8] / N52 - magnetic separator

Pros and cons of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• They are resistant to demagnetization induced by external disturbances,
• Thanks to the elegant finish, the plating of Ni-Cu-Ni, gold-plated, or silver-plated gives an visually attractive appearance,
• Neodymium magnets ensure maximum magnetic induction on a small area, which allows for strong attraction,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• In view of the potential of precise shaping and adaptation to specialized needs, magnetic components can be created in a broad palette of geometric configurations, which expands the range of possible applications,
• Key role in advanced technology sectors – they are commonly used in HDD drives, electric motors, medical equipment, as well as other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

What to avoid - cons of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability 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 casing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complicated forms.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small components of these products can disrupt the diagnostic process medical when they are in the body.
• With large orders the cost of neodymium magnets is economically unviable,

Maximum magnetic pulling force – what it depends on?

The lifting capacity listed is a measurement result performed under the following configuration:

• with the use of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• whose transverse dimension equals approx. 10 mm
• with an ground touching surface
• with total lack of distance (no paint)
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Determinants of practical lifting force of a magnet

Real force is influenced by specific conditions, mainly (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.
• 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 smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – too thin plate does not close the flux, causing part of the flux to be escaped to the other side.
• Steel grade – ideal substrate is high-permeability steel. Stainless steels may generate lower lifting capacity.
• Plate texture – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces weaken the grip.
• Thermal environment – temperature increase causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was determined with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under vertically applied force, however under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.