SM 32x450 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have constant strength, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They feature excellent resistance to magnetic field loss when exposed to external fields,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to present itself better,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to the ability of free molding and adaptation to custom needs, NdFeB magnets can be manufactured in a wide range of geometric configurations, which increases their versatility,
• Key role in future technologies – they are used in hard drives, electric drive systems, precision medical tools, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which makes them useful in miniature devices

What to avoid - cons of neodymium magnets: tips and applications.

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Limited possibility of creating nuts in the magnet and complex shapes - recommended is a housing - mounting mechanism.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these devices can be problematic in diagnostics medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Magnetic strength at its maximum – what affects it?

The lifting capacity listed is a result of laboratory testing performed under standard conditions:

• using a sheet made of low-carbon steel, acting as a ideal flux conductor
• with a cross-section no less than 10 mm
• with an polished contact surface
• without any air gap between the magnet and steel
• under axial force vector (90-degree angle)
• in stable room temperature

Impact of factors on magnetic holding capacity in practice

Effective lifting capacity is affected by working environment parameters, mainly (from priority):

• Air gap (betwixt the magnet and the plate), since even a tiny distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – highest force is reached only during pulling at a 90° angle. The shear force of the magnet along the plate is usually many times smaller (approx. 1/5 of the lifting capacity).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
• Smoothness – ideal contact is obtained only on polished steel. Any scratches and bumps create air cushions, reducing force.
• Temperature influence – high temperature weakens pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity was measured with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate lowers the load capacity.