SMZR 25x250 / N52 - magnetic separator with handle

Advantages as well as disadvantages of neodymium magnets.

Apart from their notable holding force, neodymium magnets have these key benefits:

• They have constant strength, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• Magnets perfectly resist against loss of magnetization caused by external fields,
• The use of an shiny finish of noble metals (nickel, gold, silver) causes the element to look better,
• They are known for high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Thanks to freedom in designing and the capacity to modify to client solutions,
• Wide application in innovative solutions – they find application in magnetic memories, electric motors, advanced medical instruments, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which enables their usage in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest a housing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex forms.
• Possible danger to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, small components of these magnets are able to disrupt the diagnostic process medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

Best holding force of the magnet in ideal parameters – what it depends on?

Information about lifting capacity was determined for ideal contact conditions, assuming:

• using a plate made of mild steel, acting as a magnetic yoke
• with a cross-section no less than 10 mm
• with a surface cleaned and smooth
• with direct contact (no paint)
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

It is worth knowing that the magnet holding will differ influenced by the following factors, in order of importance:

• Distance – the presence of any layer (rust, tape, air) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Material type – the best choice is pure iron steel. Stainless steels may attract less.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the load capacity is reduced by as much as fivefold. In addition, even a small distance {between} the magnet and the plate decreases the load capacity.