SM 25x225 [2xM8] / N52 - magnetic separator

Pros as well as cons of NdFeB magnets.

Apart from their strong holding force, neodymium magnets have these key benefits:

• Their power remains stable, and after around ten years it drops only by ~1% (theoretically),
• They maintain their magnetic properties even under strong external field,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• The surface of neodymium magnets generates a intense magnetic field – this is a distinguishing feature,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of custom modeling and modifying to concrete applications,
• Huge importance in innovative solutions – they are utilized in computer drives, electric drive systems, advanced medical instruments, as well as other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• Limited ability of producing threads in the magnet and complicated shapes - preferred is cover - mounting mechanism.
• Possible danger resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these magnets are able to complicate diagnosis medical in case of swallowing.
• With budget limitations the cost of neodymium magnets can be a barrier,

Maximum magnetic pulling force – what contributes to it?

The specified lifting capacity concerns the peak performance, obtained under laboratory conditions, specifically:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• whose thickness reaches at least 10 mm
• with a surface cleaned and smooth
• with total lack of distance (no coatings)
• during pulling in a direction perpendicular to the plane
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

Holding efficiency is affected by working environment parameters, including (from priority):

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Steel thickness – too thin steel does not accept the full field, causing part of the flux to be lost into the air.
• Material composition – different alloys attracts identically. High carbon content worsen the interaction with the magnet.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of suitable thickness, under perpendicular forces, whereas under parallel forces the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the lifting capacity.