SM 32x250 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They do not lose power, even during around 10 years – the decrease in lifting capacity is only ~1% (according to tests),
• They maintain their magnetic properties even under close interference source,
• Thanks to the metallic finish, the coating of Ni-Cu-Ni, gold, or silver gives an aesthetic appearance,
• Magnetic induction on the working layer of the magnet turns out to be exceptional,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Thanks to flexibility in constructing and the capacity to customize to individual projects,
• Fundamental importance in electronics industry – they are commonly used in magnetic memories, electric motors, advanced medical instruments, as well as other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Cons of neodymium magnets: tips and applications.

• Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• Neodymium magnets lose their strength 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• We recommend cover - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these products are able to disrupt the diagnostic process 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 capacity of the magnet – what it depends on?

Holding force of 0 kg is a measurement result conducted under the following configuration:

• with the contact of a sheet made of low-carbon steel, ensuring full magnetic saturation
• with a cross-section minimum 10 mm
• characterized by smoothness
• under conditions of no distance (metal-to-metal)
• under perpendicular application of breakaway force (90-degree angle)
• in neutral thermal conditions

Determinants of practical lifting force of a magnet

During everyday use, the actual holding force results from several key aspects, listed from most significant:

• Space between magnet and steel – every millimeter of separation (caused e.g. by veneer or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Load vector – maximum parameter is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is usually several times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Material type – the best choice is pure iron steel. Cast iron may attract less.
• Plate texture – ground elements guarantee perfect abutment, which increases field saturation. Uneven metal reduce efficiency.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.