SM 25x200 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

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

• Their magnetic field is maintained, and after approximately 10 years it drops only by ~1% (theoretically),
• They are extremely resistant to demagnetization induced by external disturbances,
• By using a smooth coating of gold, the element acquires an professional look,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Considering the option of flexible shaping and adaptation to specialized requirements, neodymium magnets can be manufactured in a wide range of forms and dimensions, which increases their versatility,
• Key role in high-tech industry – they find application in magnetic memories, drive modules, medical devices, and multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in strength. 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• We recommend a housing - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated shapes.
• Possible danger resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these magnets can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Magnetic strength at its maximum – what contributes to it?

The force parameter is a theoretical maximum value performed under standard conditions:

• on a base made of structural steel, effectively closing the magnetic flux
• whose thickness is min. 10 mm
• with an ideally smooth contact surface
• without any insulating layer between the magnet and steel
• under axial force direction (90-degree angle)
• at conditions approx. 20°C

Determinants of lifting force in real conditions

Bear in mind that the application force may be lower subject to elements below, in order of importance:

• Gap (betwixt the magnet and the metal), as even a tiny clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to varnish, rust or debris).
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Base massiveness – too thin steel does not close the flux, causing part of the power to be wasted into the air.
• Material type – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Base smoothness – the more even the surface, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.