SM 18x275 [2xM5] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

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

• Their power remains stable, and after around ten years it decreases only by ~1% (theoretically),
• They have excellent resistance to weakening of magnetic properties as a result of external fields,
• In other words, due to the metallic surface of silver, the element looks attractive,
• They feature high magnetic induction at the operating surface, which increases their power,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• In view of the option of accurate molding and adaptation to individualized needs, magnetic components can be manufactured in a variety of forms and dimensions, which amplifies use scope,
• Significant place in modern technologies – they are utilized in computer drives, brushless drives, advanced medical instruments, and other advanced devices.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Cons of neodymium magnets and ways of using them

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its 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 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material immune to moisture, when using outdoors
• Limited possibility of making threads in the magnet and complex shapes - preferred is casing - magnet mounting.
• Health risk related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, small elements of these magnets are able to be problematic in diagnostics medical when they are in the body.
• With mass production the cost of neodymium magnets is a challenge,

Maximum lifting force for a neodymium magnet – what contributes to it?

Magnet power was defined for optimal configuration, assuming:

• using a plate made of mild steel, functioning as a ideal flux conductor
• whose thickness equals approx. 10 mm
• with an ground contact surface
• with direct contact (no paint)
• under perpendicular application of breakaway force (90-degree angle)
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

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

• Air gap (betwixt the magnet and the metal), since even a microscopic clearance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to varnish, rust or debris).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick plate does not close the flux, causing part of the power to be lost to the other side.
• Plate material – low-carbon steel attracts best. Alloy steels lower magnetic properties and holding force.
• Surface condition – ground elements ensure maximum contact, which improves field saturation. Uneven metal reduce efficiency.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.