SM 25x225 [2xM8] / N42 - magnetic separator

Strengths and weaknesses of NdFeB magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• Their strength is maintained, and after approximately 10 years it decreases only by ~1% (according to research),
• They are resistant to demagnetization induced by presence of other magnetic fields,
• A magnet with a smooth gold surface has better aesthetics,
• They show high magnetic induction at the operating surface, which increases their power,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Due to the potential of precise forming and customization to custom needs, NdFeB magnets can be modeled in a wide range of forms and dimensions, which expands the range of possible applications,
• Significant place in electronics industry – they are commonly used in computer drives, electromotive mechanisms, medical devices, as well as complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We suggest cover - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated forms.
• Possible danger resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small components of these magnets can disrupt the diagnostic process medical after entering the body.
• With mass production the cost of neodymium magnets is economically unviable,

Maximum lifting capacity of the magnet – what contributes to it?

The lifting capacity listed is a measurement result executed under specific, ideal conditions:

• on a plate made of structural steel, effectively closing the magnetic field
• whose transverse dimension reaches at least 10 mm
• with a plane cleaned and smooth
• under conditions of ideal adhesion (surface-to-surface)
• under vertical force vector (90-degree angle)
• at temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

It is worth knowing that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Gap (betwixt the magnet and the plate), since even a tiny distance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet limits the attraction force (the magnet "punches through" it).
• Metal type – not every steel attracts identically. Alloy additives worsen the attraction effect.
• Surface condition – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet and the plate lowers the holding force.