SMZR 25x150 / N52 - magnetic separator with handle

Strengths and weaknesses of neodymium magnets.

Besides their stability, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They do not lose their magnetic properties even under close interference source,
• By using a shiny layer of silver, the element gains an nice look,
• Magnetic induction on the top side of the magnet is strong,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of exact modeling as well as optimizing to atypical applications,
• Key role in future technologies – they find application in magnetic memories, motor assemblies, medical equipment, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which allows their use in compact constructions

What to avoid - cons of neodymium magnets and ways of using them

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 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, when using outdoors
• Limited ability of making threads in the magnet and complex forms - recommended is a housing - magnetic holder.
• Potential hazard resulting from small fragments 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 complicate diagnosis medical in case of swallowing.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting force for a neodymium magnet – what contributes to it?

The lifting capacity listed is a measurement result performed under the following configuration:

• with the contact of a yoke made of low-carbon steel, ensuring full magnetic saturation
• whose thickness is min. 10 mm
• with a surface free of scratches
• without the slightest clearance between the magnet and steel
• under axial force vector (90-degree angle)
• at temperature room level

Practical lifting capacity: influencing factors

Holding efficiency is affected by working environment parameters, such as (from priority):

• Space between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Material type – ideal substrate is pure iron steel. Cast iron may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Rough surfaces weaken the grip.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was measured by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.