SM 25x350 [2xM8] / N52 - magnetic separator

Pros as well as cons of NdFeB magnets.

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

• They have unchanged lifting capacity, and over nearly 10 years their attraction force decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under external field action,
• In other words, due to the smooth surface of silver, the element gains visual value,
• Neodymium magnets achieve maximum magnetic induction on a their surface, which ensures high operational effectiveness,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures approaching 230°C and above...
• Possibility of precise forming and modifying to specific requirements,
• Significant place in modern technologies – they find application in magnetic memories, drive modules, medical equipment, and technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which allows their use in compact constructions

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a special holder, which not only protects them against impacts but also raises their durability
• Neodymium magnets decrease 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 stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited ability of producing nuts in the magnet and complex forms - preferred is casing - magnetic holder.
• Potential hazard related to microscopic parts of magnets are risky, if swallowed, which gains importance in the context of child safety. Furthermore, small elements of these products are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what affects it?

The force parameter is a measurement result performed under standard conditions:

• on a plate made of structural steel, effectively closing the magnetic field
• possessing a thickness of minimum 10 mm to ensure full flux closure
• characterized by lack of roughness
• with zero gap (no impurities)
• during detachment in a direction vertical to the plane
• at ambient temperature room level

Determinants of practical lifting force of a magnet

Real force is affected by working environment parameters, including (from most important):

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to pulling vertically. When slipping, the magnet holds much less (often approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick sheet does not close the flux, causing part of the power to be wasted to the other side.
• Steel grade – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Uneven metal reduce efficiency.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed 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 lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate decreases the holding force.