SM 32x300 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
• They maintain their magnetic properties even under close interference source,
• A magnet with a smooth gold surface is more attractive,
• Magnetic induction on the working layer of the magnet is very high,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of individual machining and adjusting to complex applications,
• Huge importance in advanced technology sectors – they are commonly used in hard drives, motor assemblies, medical equipment, as well as other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we recommend 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 power 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 usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of making nuts in the magnet and complex forms - preferred is a housing - mounting mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small components of these devices can disrupt the diagnostic process medical when they are in the body.
• With large orders the cost of neodymium magnets can be a barrier,

Magnetic strength at its maximum – what contributes to it?

Breakaway force was defined for optimal configuration, including:

• on a base made of mild steel, perfectly concentrating the magnetic flux
• whose transverse dimension is min. 10 mm
• with an polished contact surface
• under conditions of gap-free contact (surface-to-surface)
• during detachment in a direction vertical to the plane
• at ambient temperature room level

What influences lifting capacity in practice

Holding efficiency is influenced by specific conditions, including (from priority):

• Distance (between the magnet and the plate), since even a very small clearance (e.g. 0.5 mm) results in a reduction in force by up to 50% (this also applies to varnish, rust or dirt).
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of generating force.
• Plate material – mild steel gives the best results. Alloy admixtures lower magnetic permeability and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Thermal factor – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the lifting capacity.