SM 32x125 [2xM8] / N42 - magnetic separator

Pros as well as cons of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• Their power remains stable, and after around 10 years it decreases only by ~1% (theoretically),
• Magnets effectively resist against loss of magnetization caused by external fields,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to look better,
• The surface of neodymium magnets generates a maximum magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of custom forming and adapting to defined requirements,
• Wide application in innovative solutions – they are commonly used in mass storage devices, electromotive mechanisms, medical devices, as well as modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Drawbacks and weaknesses of neodymium magnets: application proposals

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 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 magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in realizing threads and complicated shapes in magnets, we propose using a housing - magnetic mount.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these magnets can disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum holding power of the magnet – what it depends on?

The lifting capacity listed is a result of laboratory testing conducted under specific, ideal conditions:

• with the use of a yoke made of low-carbon steel, ensuring maximum field concentration
• possessing a thickness of min. 10 mm to avoid saturation
• with an polished touching surface
• with direct contact (no impurities)
• under axial force vector (90-degree angle)
• in neutral thermal conditions

Practical aspects of lifting capacity – factors

Effective lifting capacity is affected by specific conditions, mainly (from most important):

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Smoothness – full contact is possible only on polished steel. Rough texture create air cushions, reducing force.
• Operating temperature – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was determined with the use of a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.