SM 25x125 [2xM8] / N52 - magnetic separator

Pros and cons of NdFeB magnets.

Apart from their consistent power, neodymium magnets have these key benefits:

• They have stable power, and over more than ten years their performance decreases symbolically – ~1% (in testing),
• They do not lose their magnetic properties even under strong external field,
• In other words, due to the shiny finish of gold, the element gains a professional look,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to flexibility in shaping and the ability to adapt to unusual requirements,
• Wide application in future technologies – they are utilized in data components, electromotive mechanisms, medical equipment, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in compact constructions

Problematic aspects of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 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 immune to moisture, when using outdoors
• Due to limitations in creating nuts and complicated forms in magnets, we recommend using casing - magnetic mechanism.
• Health risk related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small components of these devices can be problematic in diagnostics medical in case of swallowing.
• Due to expensive raw materials, their price is higher than average,

Maximum lifting capacity of the magnet – what affects it?

Breakaway force was determined for ideal contact conditions, assuming:

• on a block made of structural steel, effectively closing the magnetic flux
• possessing a thickness of min. 10 mm to ensure full flux closure
• with an ideally smooth contact surface
• without the slightest insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the plane
• at temperature room level

Impact of factors on magnetic holding capacity in practice

Bear in mind that the magnet holding may be lower subject to the following factors, in order of importance:

• Clearance – existence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to pulling vertically. When slipping, the magnet holds much less (typically approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped into the air.
• Steel grade – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal environment – heating the magnet results in weakening of induction. Check the thermal limit for a given model.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.