SM 25x250 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

Apart from their notable power, neodymium magnets have these key benefits:

• Their magnetic field is maintained, and after around 10 years it drops only by ~1% (according to research),
• They possess excellent resistance to magnetism drop due to external magnetic sources,
• Thanks to the metallic finish, the plating of Ni-Cu-Ni, gold, or silver gives an elegant appearance,
• Magnetic induction on the top side of the magnet turns out to be impressive,
• 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 accurate machining as well as adjusting to atypical applications,
• Fundamental importance in modern industrial fields – they are used in computer drives, electric motors, precision medical tools, also multitasking production systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• We suggest cover - magnetic mount, due to difficulties in creating threads inside the magnet and complicated shapes.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these devices can be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets is a challenge,

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

The declared magnet strength concerns the limit force, measured under optimal environment, specifically:

• on a block made of mild steel, optimally conducting the magnetic flux
• possessing a thickness of min. 10 mm to ensure full flux closure
• with a plane cleaned and smooth
• with total lack of distance (no impurities)
• during pulling in a direction perpendicular to the plane
• in neutral thermal conditions

Impact of factors on magnetic holding capacity in practice

Real force is influenced by specific conditions, mainly (from priority):

• Clearance – the presence of foreign body (rust, tape, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the plate is usually many times smaller (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick plate does not accept the full field, causing part of the flux to be wasted to the other side.
• Metal type – different alloys attracts identically. High carbon content worsen the attraction effect.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• 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).

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.