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

Strengths and weaknesses of NdFeB magnets.

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

• They do not lose magnetism, even during around 10 years – the decrease in strength is only ~1% (according to tests),
• Neodymium magnets are distinguished by highly resistant to loss of magnetic properties caused by magnetic disturbances,
• In other words, due to the aesthetic layer of gold, the element gains a professional look,
• Magnets are distinguished by maximum magnetic induction on the surface,
• 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...
• In view of the potential of flexible forming and adaptation to specialized requirements, NdFeB magnets can be created in a variety of forms and dimensions, which increases their versatility,
• Huge importance in advanced technology sectors – they find application in mass storage devices, electromotive mechanisms, diagnostic systems, and other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in tiny dimensions, which allows their use in compact constructions

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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
• When exposed to humidity, magnets start to 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.
• Due to limitations in creating nuts and complex forms in magnets, we propose using cover - magnetic mount.
• Potential hazard resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that tiny parts of these magnets are able to complicate diagnosis medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Optimal lifting capacity of a neodymium magnet – what it depends on?

The load parameter shown concerns the limit force, obtained under optimal environment, namely:

• on a block made of structural steel, effectively closing the magnetic field
• whose thickness equals approx. 10 mm
• with an ideally smooth touching surface
• with zero gap (no impurities)
• for force applied at a right angle (pull-off, not shear)
• in temp. approx. 20°C

Key elements affecting lifting force

In practice, the actual lifting capacity is determined by several key aspects, listed from the most important:

• Distance (between the magnet and the plate), as even a very small distance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to paint, corrosion or dirt).
• Loading method – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Material type – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
• Base smoothness – the more even the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Thermal environment – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, however under shearing force the load capacity is reduced by as much as fivefold. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.