SM 25x225 [2xM8] / N52 - magnetic separator

Pros as well as cons of rare earth magnets.

Besides their exceptional field intensity, neodymium magnets offer the following advantages:

• Their magnetic field is maintained, and after approximately ten years it drops only by ~1% (according to research),
• They maintain their magnetic properties even under close interference source,
• A magnet with a shiny nickel surface has better aesthetics,
• Magnetic induction on the surface of the magnet remains exceptional,
• Thanks to resistance to high temperature, they are able to function (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to flexibility in shaping and the capacity to adapt to client solutions,
• Universal use in innovative solutions – they are used in mass storage devices, brushless drives, medical devices, as well as industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
• We recommend casing - magnetic holder, due to difficulties in creating threads inside the magnet and complicated shapes.
• Possible danger related to microscopic parts of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small elements of these magnets are able to complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what affects it?

The lifting capacity listed is a measurement result performed under standard conditions:

• using a sheet made of mild steel, serving as a circuit closing element
• whose transverse dimension is min. 10 mm
• with an ideally smooth contact surface
• with zero gap (no impurities)
• during detachment in a direction perpendicular to the plane
• at temperature room level

Magnet lifting force in use – key factors

In practice, the real power is determined by several key aspects, listed from most significant:

• Clearance – the presence of foreign body (paint, dirt, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Steel thickness – too thin plate causes magnetic saturation, causing part of the flux to be escaped into the air.
• Plate material – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and lifting capacity.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Temperature influence – hot environment reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured with the use of a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate lowers the load capacity.