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

Advantages as well as disadvantages of NdFeB magnets.

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

• They do not lose magnetism, even during nearly 10 years – the drop in lifting capacity is only ~1% (according to tests),
• They maintain their magnetic properties even under external field action,
• In other words, due to the aesthetic layer of silver, the element gains visual value,
• Magnets have excellent magnetic induction on the surface,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures approaching 230°C and above...
• Thanks to modularity in shaping and the capacity to modify to specific needs,
• Huge importance in future technologies – they are commonly used in mass storage devices, motor assemblies, diagnostic systems, and industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation as well as corrosion.
• Due to limitations in realizing nuts and complicated forms in magnets, we recommend using a housing - magnetic mount.
• Health risk to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that small components of these magnets can complicate diagnosis medical in case of swallowing.
• Due to expensive raw materials, their price exceeds standard values,

Best holding force of the magnet in ideal parameters – what affects it?

The load parameter shown refers to the limit force, obtained under laboratory conditions, specifically:

• with the application of a sheet made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by smoothness
• without the slightest insulating layer between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

It is worth knowing that the application force will differ influenced by elements below, in order of importance:

• Distance – existence of any layer (paint, dirt, gap) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
• Surface finish – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the load capacity is reduced by as much as 75%. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.