SM 18x200 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

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

• Their strength is durable, and after approximately ten years it decreases only by ~1% (according to research),
• They show high resistance to demagnetization induced by external magnetic fields,
• By covering with a lustrous layer of gold, the element has an professional look,
• The surface of neodymium magnets generates a strong magnetic field – this is a distinguishing feature,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of individual creating and modifying to concrete requirements,
• Significant place in electronics industry – they are used in hard drives, electric drive systems, precision medical tools, and other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complicated shapes in magnets, we recommend using casing - magnetic mount.
• Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, small components of these products are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what contributes to it?

The declared magnet strength refers to the limit force, measured under optimal environment, specifically:

• using a sheet made of low-carbon steel, functioning as a ideal flux conductor
• whose thickness is min. 10 mm
• with an polished touching surface
• without any clearance between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at standard ambient temperature

Determinants of lifting force in real conditions

In practice, the actual holding force depends on many variables, presented from crucial:

• Gap between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Material type – the best choice is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface condition – ground elements ensure maximum contact, which improves force. Rough surfaces weaken the grip.
• Temperature – heating the magnet causes a temporary drop of force. Check the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate lowers the holding force.