SM 18x275 [2xM5] / N42 - magnetic separator

Pros and cons of neodymium magnets.

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

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (according to literature),
• They are extremely resistant to demagnetization induced by external field influence,
• By covering with a shiny layer of silver, the element has an elegant look,
• They show high magnetic induction at the operating surface, which improves attraction properties,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in forming and the capacity to adapt to unusual requirements,
• Huge importance in advanced technology sectors – they find application in computer drives, drive modules, precision medical tools, as well as complex engineering applications.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which makes them useful in compact constructions

Disadvantages of neodymium magnets:

• At very strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Limited ability of producing nuts in the magnet and complicated forms - recommended is cover - magnetic holder.
• Potential hazard to health – tiny shards of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these products can disrupt the diagnostic process medical after entering the body.
• Due to expensive raw materials, their price is relatively high,

Detachment force of the magnet in optimal conditions – what affects it?

Magnet power is the result of a measurement for the most favorable conditions, taking into account:

• using a sheet made of low-carbon steel, serving as a magnetic yoke
• possessing a thickness of min. 10 mm to avoid saturation
• with a plane perfectly flat
• without any air gap between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• in neutral thermal conditions

Magnet lifting force in use – key factors

Real force impacted by specific conditions, such as (from most important):

• Distance (betwixt the magnet and the plate), because even a microscopic clearance (e.g. 0.5 mm) leads to a decrease in force by up to 50% (this also applies to varnish, rust or debris).
• Loading method – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Metal type – different alloys attracts identically. Alloy additives worsen the attraction effect.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.