SM 18x175 [2xM5] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

Apart from their notable holding force, neodymium magnets have these key benefits:

• Their strength is maintained, and after approximately 10 years it drops only by ~1% (theoretically),
• They are extremely resistant to demagnetization induced by external magnetic fields,
• The use of an metallic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Neodymium magnets generate maximum magnetic induction on a small area, which increases force concentration,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• In view of the potential of free forming and customization to individualized needs, magnetic components can be created in a variety of geometric configurations, which increases their versatility,
• Wide application in future technologies – they are commonly used in magnetic memories, drive modules, medical equipment, and other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Problematic aspects of neodymium magnets: application proposals

• At very strong impacts they can break, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their power 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 magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited possibility of creating threads in the magnet and complex shapes - preferred is casing - magnetic holder.
• Potential hazard resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the context of child health protection. Additionally, small elements of these devices can complicate diagnosis medical when they are in the body.
• With large orders the cost of neodymium magnets can be a barrier,

Highest magnetic holding force – what affects it?

Magnet power was determined for ideal contact conditions, taking into account:

• on a block made of structural steel, effectively closing the magnetic field
• with a cross-section no less than 10 mm
• characterized by even structure
• under conditions of gap-free contact (surface-to-surface)
• during pulling in a direction vertical to the plane
• at room temperature

Lifting capacity in real conditions – factors

During everyday use, the actual holding force is determined by several key aspects, ranked from crucial:

• Air gap (betwixt the magnet and the plate), because even a tiny distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick steel causes magnetic saturation, causing part of the flux to be wasted to the other side.
• Material composition – not every steel attracts identically. High carbon content weaken the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.