SM 32x225 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

Apart from their strong power, neodymium magnets have these key benefits:

• They have stable power, and over around 10 years their performance decreases symbolically – ~1% (according to theory),
• They are extremely resistant to demagnetization induced by presence of other magnetic fields,
• In other words, due to the metallic finish of gold, the element is aesthetically pleasing,
• The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to flexibility in designing and the capacity to modify to complex applications,
• Fundamental importance in modern industrial fields – they find application in HDD drives, drive modules, diagnostic systems, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

What to avoid - cons of neodymium magnets and proposals for their use:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• 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 as well as corrosion.
• Due to limitations in realizing nuts and complex forms in magnets, we propose using cover - magnetic mount.
• Possible danger resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, small components of these devices are able to disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Magnetic strength at its maximum – what contributes to it?

Magnet power is the result of a measurement for ideal contact conditions, taking into account:

• with the use of a sheet made of special test steel, guaranteeing full magnetic saturation
• whose transverse dimension is min. 10 mm
• with an ideally smooth contact surface
• under conditions of ideal adhesion (surface-to-surface)
• during pulling in a direction vertical to the mounting surface
• in stable room temperature

Key elements affecting lifting force

In practice, the actual holding force results from a number of factors, presented from most significant:

• Distance – existence of foreign body (paint, dirt, gap) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
• Angle of force application – highest force is available only during perpendicular pulling. The shear force of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of converting into lifting capacity.
• Metal type – different alloys reacts the same. High carbon content weaken the attraction effect.
• Surface finish – ideal contact is obtained only on polished steel. Rough texture reduce the real contact area, reducing force.
• Temperature influence – hot environment weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the holding force.