SM 25x150 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They retain full power for around ten years – the drop is just ~1% (according to analyses),
• They maintain their magnetic properties even under close interference source,
• Thanks to the smooth finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an elegant appearance,
• Magnets are distinguished by extremely high magnetic induction on the outer side,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of precise creating as well as modifying to precise applications,
• Wide application in advanced technology sectors – they find application in mass storage devices, drive modules, advanced medical instruments, and multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and proposals for their use:

• At very strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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 - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We suggest a housing - magnetic holder, due to difficulties in producing nuts inside the magnet and complicated forms.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the context of child health protection. Furthermore, small components of these magnets can complicate diagnosis medical when they are in the body.
• With budget limitations the cost of neodymium magnets is a challenge,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The specified lifting capacity concerns the maximum value, recorded under optimal environment, specifically:

• using a plate made of low-carbon steel, functioning as a circuit closing element
• with a cross-section minimum 10 mm
• with a plane perfectly flat
• under conditions of gap-free contact (surface-to-surface)
• during pulling in a direction vertical to the mounting surface
• at conditions approx. 20°C

Impact of factors on magnetic holding capacity in practice

Real force is influenced by specific conditions, including (from priority):

• Distance (between the magnet and the metal), as even a microscopic clearance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Direction of force – maximum parameter is available only during perpendicular pulling. The shear force of the magnet along the plate is typically many times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content decrease magnetic permeability and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet and the plate reduces the load capacity.