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

Advantages as well as disadvantages of neodymium magnets.

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

• They do not lose strength, even after around 10 years – the drop in strength is only ~1% (theoretically),
• Neodymium magnets are exceptionally resistant to magnetic field loss caused by external magnetic fields,
• By applying a decorative coating of gold, the element presents an 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 shape) at temperatures up to 230°C and above...
• Thanks to flexibility in constructing and the capacity to adapt to specific needs,
• Huge importance in future technologies – they find application in computer drives, electromotive mechanisms, diagnostic systems, also multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets and proposals for their use:

• At very strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• 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.
• We suggest casing - magnetic holder, due to difficulties in producing nuts inside the magnet and complicated shapes.
• Possible danger related to microscopic parts of magnets are risky, if swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

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

Information about lifting capacity was determined for the most favorable conditions, including:

• with the use of a yoke made of low-carbon steel, ensuring maximum field concentration
• with a cross-section of at least 10 mm
• with a plane cleaned and smooth
• with total lack of distance (without coatings)
• under perpendicular force vector (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

In practice, the real power results from a number of factors, ranked from most significant:

• Distance (betwixt the magnet and the plate), as even a microscopic distance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Angle of force application – maximum parameter is available only during pulling at a 90° angle. The shear force of the magnet along the plate is standardly many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the lifting capacity.