SM 18x200 [2xM5] / N42 - magnetic separator

Strengths and weaknesses of neodymium magnets.

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

• They retain full power for nearly 10 years – the loss is just ~1% (based on simulations),
• They are resistant to demagnetization induced by external field influence,
• A magnet with a smooth gold surface looks better,
• The surface of neodymium magnets generates a intense magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to freedom in forming and the ability to customize to complex applications,
• Fundamental importance in modern industrial fields – they serve a role in magnetic memories, drive modules, diagnostic systems, as well as multitasking production systems.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• At strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in producing threads and complex forms in magnets, we recommend using cover - magnetic holder.
• Health risk related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum magnetic pulling force – what contributes to it?

The declared magnet strength represents the limit force, obtained under optimal environment, meaning:

• with the contact of a sheet made of special test steel, guaranteeing maximum field concentration
• with a thickness no less than 10 mm
• with a plane perfectly flat
• under conditions of ideal adhesion (surface-to-surface)
• during detachment in a direction perpendicular to the mounting surface
• in temp. approx. 20°C

What influences lifting capacity in practice

Real force is affected by specific conditions, such as (from most important):

• Space between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum 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 – the best choice is high-permeability steel. Cast iron may attract less.
• Smoothness – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature – heating the magnet results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet and the plate decreases the lifting capacity.