SM 18x275 [2xM5] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• Magnets perfectly resist against demagnetization caused by ambient magnetic noise,
• A magnet with a shiny silver surface has an effective appearance,
• They are known for high magnetic induction at the operating surface, which increases their power,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Due to the option of accurate shaping and customization to custom projects, magnetic components can be manufactured in a broad palette of shapes and sizes, which increases their versatility,
• Wide application in innovative solutions – they find application in hard drives, motor assemblies, diagnostic systems, and modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce 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 creating nuts in the magnet and complex shapes - recommended is cover - magnetic holder.
• Potential hazard resulting from small fragments of magnets are risky, in case of ingestion, which gains importance in the context of child safety. Furthermore, small components of these products can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what affects it?

The load parameter shown represents the maximum value, obtained under ideal test conditions, namely:

• using a plate made of low-carbon steel, serving as a magnetic yoke
• whose transverse dimension reaches at least 10 mm
• characterized by smoothness
• with total lack of distance (without paint)
• during detachment in a direction perpendicular to the plane
• at standard ambient temperature

Lifting capacity in practice – influencing factors

In real-world applications, the actual holding force is determined by many variables, listed from most significant:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Angle of force application – maximum parameter is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Wall 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.
• Plate material – low-carbon steel attracts best. Higher carbon content lower magnetic permeability and holding force.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Operating temperature – neodymium magnets have a sensitivity to temperature. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Lifting capacity testing was carried out on a smooth plate of suitable thickness, under perpendicular forces, however under parallel forces the load capacity is reduced by as much as 75%. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.