SM 32x150 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (in testing),
• Neodymium magnets are exceptionally resistant to loss of magnetic properties caused by external magnetic fields,
• Thanks to the smooth finish, the coating of Ni-Cu-Ni, gold, or silver gives an visually attractive appearance,
• The surface of neodymium magnets generates a intense magnetic field – this is a key feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling functioning at temperatures approaching 230°C and above...
• Possibility of individual shaping as well as adjusting to atypical conditions,
• Universal use in high-tech industry – they are commonly used in HDD drives, electric motors, advanced medical instruments, as well as industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a strong case, which not only secures them against impacts but also increases their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (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
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in realizing threads and complex shapes in magnets, we recommend using casing - magnetic mount.
• Potential hazard related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these magnets are able to complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum holding power of the magnet – what contributes to it?

Information about lifting capacity was determined for ideal contact conditions, including:

• with the contact of a yoke made of low-carbon steel, ensuring full magnetic saturation
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a plane free of scratches
• without any insulating layer between the magnet and steel
• under vertical force vector (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

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

• Gap (betwixt the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to paint, corrosion or debris).
• Load vector – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is usually several times smaller (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).
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content reduce magnetic properties and holding force.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Temperature – temperature increase results in weakening of induction. Check the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.