SM 32x400 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

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

• Their strength is durable, and after around ten years it drops only by ~1% (according to research),
• Magnets perfectly protect themselves against loss of magnetization caused by ambient magnetic noise,
• In other words, due to the metallic layer of gold, the element gains a professional look,
• Neodymium magnets achieve maximum magnetic induction on a small area, which allows for strong attraction,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Considering the option of accurate forming and adaptation to specialized needs, magnetic components can be created in a variety of forms and dimensions, which amplifies use scope,
• Fundamental importance in advanced technology sectors – they serve a role in HDD drives, electric drive systems, diagnostic systems, also modern systems.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution protects the magnet and simultaneously increases 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 stability even at temperatures up to 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 resistant to moisture, when using outdoors
• We recommend casing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the context of child safety. Additionally, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets is economically unviable,

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

Magnet power was defined for optimal configuration, including:

• using a sheet made of low-carbon steel, functioning as a circuit closing element
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• without any insulating layer between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

In practice, the real power depends on several key aspects, ranked from most significant:

• Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin steel does not accept the full field, causing part of the flux to be wasted to the other side.
• Material composition – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Temperature – temperature increase results in weakening of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of suitable thickness, under perpendicular forces, 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 lifting capacity.