SM 18x200 [2xM5] / N42 - magnetic separator

Advantages as well as disadvantages of NdFeB magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• Their strength is durable, and after approximately ten years it drops only by ~1% (according to research),
• Neodymium magnets are exceptionally resistant to loss of magnetic properties caused by external interference,
• By applying a decorative coating of silver, the element acquires an aesthetic look,
• The surface of neodymium magnets generates a maximum magnetic field – this is one of their assets,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to flexibility in designing and the capacity to modify to unusual requirements,
• Key role in innovative solutions – they are commonly used in hard drives, electromotive mechanisms, advanced medical instruments, also multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which makes them useful in compact constructions

Cons of neodymium magnets: application proposals

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• Neodymium magnets decrease their force 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 durability even at temperatures up to 230°C
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest cover - magnetic holder, due to difficulties in creating threads inside the magnet and complicated forms.
• Potential hazard related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Additionally, small components of these products can disrupt the diagnostic process medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Optimal lifting capacity of a neodymium magnet – what it depends on?

The load parameter shown refers to the maximum value, recorded under laboratory conditions, namely:

• using a sheet made of high-permeability steel, acting as a magnetic yoke
• possessing a thickness of minimum 10 mm to ensure full flux closure
• characterized by lack of roughness
• with total lack of distance (no impurities)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Lifting capacity in real conditions – factors

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

• Gap (betwixt the magnet and the metal), because even a very small distance (e.g. 0.5 mm) results in a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the flux to be escaped to the other side.
• Metal type – not every steel attracts identically. High carbon content weaken the interaction with the magnet.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Thermal factor – hot environment weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the lifting capacity.