SM 18x175 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

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

• They do not lose power, even after nearly ten years – the drop in strength is only ~1% (based on measurements),
• They retain their magnetic properties even under strong external field,
• By using a reflective coating of silver, the element presents an modern look,
• The surface of neodymium magnets generates a powerful magnetic field – this is a distinguishing feature,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of precise shaping as well as adapting to precise conditions,
• Significant place in modern technologies – they serve a role in mass storage devices, drive modules, medical devices, also multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets and ways of using them

• To avoid cracks under impact, we recommend using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• NdFeB magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 extremely resistant to heat
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation and corrosion.
• Due to limitations in creating nuts and complicated shapes in magnets, we recommend using casing - magnetic mount.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the context of child safety. Furthermore, small elements of these products are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what affects it?

The lifting capacity listed is a measurement result executed under standard conditions:

• using a plate made of low-carbon steel, functioning as a circuit closing element
• whose transverse dimension reaches at least 10 mm
• characterized by lack of roughness
• without the slightest clearance between the magnet and steel
• under perpendicular force vector (90-degree angle)
• in neutral thermal conditions

Lifting capacity in real conditions – factors

Bear in mind that the application force will differ influenced by the following factors, starting with the most relevant:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Alloy steels decrease magnetic properties and holding force.
• Plate texture – ground elements ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Temperature influence – hot environment reduces magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under attempts to slide the magnet the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate decreases the holding force.