SM 32x400 [2xM8] / N42 - magnetic separator

Pros and cons of NdFeB magnets.

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

• They have unchanged lifting capacity, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Magnets effectively defend themselves against loss of magnetization caused by foreign field sources,
• By applying a lustrous coating of gold, the element presents an professional look,
• The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Thanks to freedom in forming and the ability to customize to client solutions,
• Versatile presence in modern industrial fields – they find application in HDD drives, brushless drives, diagnostic systems, as well as multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a strong case, 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 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
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Due to limitations in producing nuts and complex forms in magnets, we propose using a housing - magnetic mechanism.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which gains importance in the context of child safety. It is also worth noting that small components of these devices are able to complicate diagnosis medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what affects it?

The declared magnet strength concerns the maximum value, measured under ideal test conditions, namely:

• using a plate made of high-permeability steel, functioning as a magnetic yoke
• whose transverse dimension is min. 10 mm
• with a surface perfectly flat
• without the slightest insulating layer between the magnet and steel
• under axial force direction (90-degree angle)
• at temperature room level

Practical lifting capacity: influencing factors

It is worth knowing that the application force will differ depending on elements below, starting with the most relevant:

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Chemical composition of the base – mild steel attracts best. Alloy steels reduce magnetic properties and holding force.
• Surface finish – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as 75%. In addition, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.