SM 18x150 [2xM5] / N42 - magnetic separator

Pros and cons of neodymium magnets.

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

• Their magnetic field is maintained, and after around ten years it drops only by ~1% (according to research),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• In other words, due to the smooth layer of gold, the element gains a professional look,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• 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 accurate machining as well as optimizing to defined conditions,
• Versatile presence in advanced technology sectors – they serve a role in hard drives, electric drive systems, advanced medical instruments, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 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 and corrosion.
• We suggest a housing - magnetic mount, due to difficulties in realizing nuts inside the magnet and complicated shapes.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small components of these products are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what affects it?

The specified lifting capacity represents the limit force, measured under optimal environment, namely:

• on a base made of mild steel, effectively closing the magnetic field
• possessing a thickness of min. 10 mm to ensure full flux closure
• with a surface cleaned and smooth
• with zero gap (no impurities)
• for force applied at a right angle (in the magnet axis)
• in stable room temperature

Magnet lifting force in use – key factors

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

• Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is pure iron steel. Hardened steels may attract less.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Rough surfaces reduce efficiency.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.