SM 32x225 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• Their magnetic field remains stable, and after around ten years it drops only by ~1% (theoretically),
• Magnets effectively defend themselves against loss of magnetization caused by external fields,
• By applying a lustrous coating of nickel, the element acquires an modern look,
• Magnets have exceptionally strong magnetic induction on the active area,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of detailed forming and modifying to concrete applications,
• Huge importance in electronics industry – they find application in magnetic memories, brushless drives, precision medical tools, also multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and ways of using them

• At strong impacts they can break, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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 usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest cover - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated forms.
• Potential hazard to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. It is also worth noting that small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• Due to complex production process, their price is relatively high,

Maximum magnetic pulling force – what affects it?

The force parameter is a theoretical maximum value executed under the following configuration:

• on a base made of mild steel, perfectly concentrating the magnetic field
• whose transverse dimension equals approx. 10 mm
• with an polished touching surface
• under conditions of no distance (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• at standard ambient temperature

Magnet lifting force in use – key factors

In real-world applications, the actual holding force results from a number of factors, presented from most significant:

• Gap between surfaces – every millimeter of distance (caused e.g. by veneer or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of generating force.
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content reduce magnetic properties and holding force.
• Surface quality – the more even the surface, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, however under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet and the plate decreases the lifting capacity.