SMZR 32x125 / N52 - magnetic separator with handle

Advantages and disadvantages of NdFeB magnets.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• They retain magnetic properties for almost ten years – the loss is just ~1% (according to analyses),
• They show high resistance to demagnetization induced by external field influence,
• A magnet with a smooth nickel surface has an effective appearance,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• 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 the option of precise forming and customization to custom solutions, NdFeB magnets can be produced in a wide range of forms and dimensions, which makes them more universal,
• Versatile presence in advanced technology sectors – they are utilized in mass storage devices, electric motors, advanced medical instruments, also technologically advanced constructions.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a special holder, which not only protects them against impacts but also increases their durability
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which gains importance in the context of child health protection. It is also worth noting that small components 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

Highest magnetic holding force – what it depends on?

Magnet power is the result of a measurement for the most favorable conditions, assuming:

• on a base made of structural steel, optimally conducting the magnetic field
• whose thickness reaches at least 10 mm
• characterized by smoothness
• without any clearance between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

Effective lifting capacity impacted by specific conditions, including (from priority):

• Clearance – existence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which reduces power rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
• Material type – ideal substrate is pure iron steel. Cast iron may attract less.
• Smoothness – ideal contact is possible only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate lowers the holding force.