SM 25x250 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (according to literature),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• By applying a shiny coating of gold, the element acquires an aesthetic look,
• The surface of neodymium magnets generates a intense magnetic field – this is one of their assets,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Thanks to freedom in constructing and the capacity to customize to unusual requirements,
• Wide application in innovative solutions – they serve a role in computer drives, electric drive systems, diagnostic systems, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• Due to limitations in realizing threads and complicated forms in magnets, we recommend using a housing - magnetic holder.
• Possible danger to health – tiny shards of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• Due to complex production process, their price is higher than average,

Magnetic strength at its maximum – what it depends on?

Information about lifting capacity was determined for optimal configuration, assuming:

• on a plate made of structural steel, effectively closing the magnetic field
• whose thickness equals approx. 10 mm
• with a surface free of scratches
• without any clearance between the magnet and steel
• during detachment in a direction vertical to the mounting surface
• at standard ambient temperature

Determinants of practical lifting force of a magnet

It is worth knowing that the working load may be lower subject to the following factors, in order of importance:

• Space between magnet and steel – every millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds much less (typically approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the power to be lost to the other side.
• Steel grade – the best choice is pure iron steel. Hardened steels may generate lower lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Thermal environment – heating the magnet causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

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