SM 25x175 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of rare earth magnets.

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

• They do not lose magnetism, even over approximately ten years – the decrease in strength is only ~1% (according to tests),
• They are noted for resistance to demagnetization induced by presence of other magnetic fields,
• In other words, due to the glossy surface of silver, the element becomes visually attractive,
• They show high magnetic induction at the operating surface, making them more effective,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Due to the option of flexible forming and adaptation to specialized solutions, NdFeB magnets can be created in a wide range of forms and dimensions, which amplifies use scope,
• Versatile presence in modern industrial fields – they find application in data components, electric drive systems, diagnostic systems, as well as technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape as well as 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 start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Limited ability of making nuts in the magnet and complicated forms - recommended is cover - magnet mounting.
• Possible danger to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, tiny parts of these devices can disrupt the diagnostic process medical in case of swallowing.
• With budget limitations the cost of neodymium magnets can be a barrier,

Detachment force of the magnet in optimal conditions – what affects it?

Magnet power is the result of a measurement for ideal contact conditions, assuming:

• with the use of a sheet made of low-carbon steel, guaranteeing full magnetic saturation
• whose transverse dimension equals approx. 10 mm
• with an ideally smooth contact surface
• without any air gap between the magnet and steel
• during detachment in a direction vertical to the plane
• at temperature approx. 20 degrees Celsius

Key elements affecting lifting force

It is worth knowing that the application force may be lower influenced by elements below, starting with the most relevant:

• Air gap (between the magnet and the plate), since even a very small distance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to varnish, rust or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
• Plate texture – ground elements guarantee perfect abutment, which increases force. Rough surfaces reduce efficiency.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.