SM 32x500 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of rare earth magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They have stable power, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They have excellent resistance to magnetism drop as a result of external fields,
• The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• 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 the option of free forming and adaptation to unique projects, neodymium magnets can be manufactured in a broad palette of geometric configurations, which expands the range of possible applications,
• Fundamental importance in future technologies – they serve a role in computer drives, electric motors, precision medical tools, and other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Problematic aspects of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• We recommend cover - magnetic holder, due to difficulties in creating threads inside the magnet and complicated shapes.
• Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

Highest magnetic holding force – what it depends on?

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

• with the application of a sheet made of low-carbon steel, ensuring full magnetic saturation
• possessing a thickness of at least 10 mm to avoid saturation
• characterized by even structure
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

Bear in mind that the magnet holding will differ subject to the following factors, starting with the most relevant:

• Gap between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during perpendicular pulling. The force required to slide of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Material composition – not every steel reacts the same. Alloy additives worsen the attraction effect.
• Base smoothness – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal factor – high temperature weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling force, however under shearing force the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate decreases the lifting capacity.