SM 25x225 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of rare earth magnets.

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

• They do not lose power, even during around 10 years – the decrease in power is only ~1% (based on measurements),
• Magnets perfectly defend themselves against loss of magnetization caused by external fields,
• By applying a smooth coating of gold, the element presents an proper look,
• Neodymium magnets deliver maximum magnetic induction on a contact point, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of individual shaping as well as adjusting to individual conditions,
• Huge importance in advanced technology sectors – they serve a role in computer drives, electric motors, precision medical tools, also other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Limited possibility of making nuts in the magnet and complex forms - recommended is a housing - mounting mechanism.
• Health risk resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. It is also worth noting that tiny parts of these devices can disrupt the diagnostic process medical after entering the body.
• Due to complex production process, their price is relatively high,

Maximum lifting capacity of the magnet – what it depends on?

The declared magnet strength concerns the maximum value, obtained under laboratory conditions, meaning:

• on a base made of structural steel, effectively closing the magnetic flux
• with a cross-section no less than 10 mm
• with a surface free of scratches
• without any insulating layer between the magnet and steel
• under axial force direction (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

Bear in mind that the working load may be lower subject to the following factors, in order of importance:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Force direction – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the flux to be escaped to the other side.
• Material type – ideal substrate is high-permeability steel. Stainless steels may have worse magnetic properties.
• Plate texture – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed by applying a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the holding force.