SM 18x150 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They retain full power for around 10 years – the loss is just ~1% (according to analyses),
• Magnets perfectly resist against demagnetization caused by external fields,
• Thanks to the shiny finish, the surface of Ni-Cu-Ni, gold, or silver-plated gives an visually attractive appearance,
• Neodymium magnets deliver maximum magnetic induction on a small area, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of accurate modeling as well as modifying to atypical requirements,
• Wide application in future technologies – they are used in hard drives, drive modules, precision medical tools, and modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which secure oxidation and corrosion.
• Limited ability of making threads in the magnet and complicated forms - preferred is casing - magnetic holder.
• Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. Additionally, small components of these products are able to be problematic in diagnostics medical after entering the body.
• With mass production the cost of neodymium magnets is economically unviable,

Breakaway strength of the magnet in ideal conditions – what affects it?

The load parameter shown refers to the limit force, recorded under laboratory conditions, namely:

• with the contact of a sheet made of special test steel, guaranteeing maximum field concentration
• with a thickness minimum 10 mm
• characterized by smoothness
• under conditions of ideal adhesion (surface-to-surface)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Key elements affecting lifting force

In real-world applications, the real power results from a number of factors, ranked from the most important:

• Distance – the presence of foreign body (paint, tape, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet exhibits significantly lower power (typically approx. 20-30% of maximum force).
• Base massiveness – insufficiently thick plate does not close the flux, causing part of the flux to be lost to the other side.
• Plate material – mild steel gives the best results. Alloy admixtures reduce magnetic permeability and holding force.
• Base smoothness – the more even the surface, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Heat – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a minimal clearance {between} the magnet and the plate lowers the load capacity.