SM 25x100 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They do not lose power, even during nearly 10 years – the decrease in lifting capacity is only ~1% (according to tests),
• They retain their magnetic properties even under strong external field,
• By applying a smooth coating of silver, the element presents an elegant look,
• Magnetic induction on the surface of the magnet is strong,
• 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...
• Possibility of precise forming as well as adapting to individual conditions,
• Wide application in innovative solutions – they find application in mass storage devices, drive modules, precision medical tools, and industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• We suggest casing - magnetic mount, due to difficulties in producing threads inside the magnet and complex forms.
• Potential hazard related to microscopic parts of magnets pose a threat, in case of ingestion, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small elements of these products can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what it depends on?

The declared magnet strength concerns the limit force, obtained under ideal test conditions, meaning:

• on a plate made of structural steel, effectively closing the magnetic flux
• possessing a thickness of min. 10 mm to avoid saturation
• with an ideally smooth touching surface
• without the slightest clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

In practice, the real power is determined by a number of factors, presented from the most important:

• Distance – existence of foreign body (rust, dirt, air) acts as an insulator, which lowers capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds much less (typically approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel gives the best results. Alloy admixtures reduce magnetic properties and holding force.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces reduce efficiency.
• Thermal environment – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the holding force.