SM 32x175 [2xM8] / N42 - magnetic separator

Pros as well as cons of neodymium magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• They retain full power for nearly 10 years – the drop is just ~1% (according to analyses),
• They are extremely resistant to demagnetization induced by external disturbances,
• By using a smooth coating of nickel, the element presents an aesthetic look,
• Magnetic induction on the working part of the magnet remains extremely intense,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures approaching 230°C and above...
• Possibility of accurate creating and modifying to atypical requirements,
• Significant place in electronics industry – they find application in computer drives, brushless drives, precision medical tools, and industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets lose their strength 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 stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• We suggest a housing - magnetic mechanism, due to difficulties in producing threads inside the magnet and complicated shapes.
• Potential hazard to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

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

The declared magnet strength refers to the peak performance, obtained under ideal test conditions, specifically:

• with the application of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a massiveness of at least 10 mm to ensure full flux closure
• characterized by even structure
• without any air gap between the magnet and steel
• during detachment in a direction perpendicular to the plane
• in stable room temperature

Lifting capacity in real conditions – factors

In practice, the actual lifting capacity depends on many variables, listed from most significant:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of maximum force).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Metal type – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Plate texture – smooth surfaces guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Thermal factor – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the holding force is lower. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.