SM 25x200 [2xM8] / N42 - magnetic separator

Pros as well as cons of rare earth magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over more than ten years their attraction force decreases symbolically – ~1% (in testing),
• They are resistant to demagnetization induced by external magnetic fields,
• The use of an shiny layer of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the working part of the magnet remains impressive,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Possibility of custom modeling as well as adjusting to precise requirements,
• Fundamental importance in innovative solutions – they find application in magnetic memories, electromotive mechanisms, medical equipment, and technologically advanced constructions.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• NdFeB magnets lose power 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 very resistant to heat
• They oxidize in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited possibility of making nuts in the magnet and complicated shapes - preferred is cover - magnet mounting.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these products can complicate diagnosis medical after entering the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

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

The specified lifting capacity concerns the maximum value, recorded under ideal test conditions, specifically:

• using a base made of mild steel, functioning as a magnetic yoke
• possessing a massiveness of min. 10 mm to avoid saturation
• with an polished touching surface
• with zero gap (without paint)
• under vertical force vector (90-degree angle)
• at conditions approx. 20°C

Key elements affecting lifting force

During everyday use, the actual holding force depends on a number of factors, presented from crucial:

• Gap between surfaces – every millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Angle of force application – maximum parameter is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Material type – ideal substrate is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Thermal factor – hot environment weakens pulling force. Too high temperature can permanently damage the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet and the plate lowers the load capacity.