SMZR 32x100 / N52 - magnetic separator with handle

Strengths as well as weaknesses of rare earth magnets.

Apart from their strong magnetism, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (according to literature),
• They are resistant to demagnetization induced by external field influence,
• A magnet with a shiny nickel surface has an effective appearance,
• The surface of neodymium magnets generates a intense magnetic field – this is a key feature,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures approaching 230°C and above...
• Due to the ability of free forming and customization to individualized projects, magnetic components can be produced in a wide range of geometric configurations, which amplifies use scope,
• Universal use in advanced technology sectors – they are used in mass storage devices, motor assemblies, diagnostic systems, and other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. 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 suggest 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 complicated shapes - preferred is casing - mounting mechanism.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, small components of these products can be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price is relatively high,

Detachment force of the magnet in optimal conditions – what affects it?

The force parameter is a result of laboratory testing conducted under standard conditions:

• on a plate made of mild steel, optimally conducting the magnetic flux
• possessing a massiveness of minimum 10 mm to avoid saturation
• with an ideally smooth contact surface
• with zero gap (without impurities)
• for force applied at a right angle (pull-off, not shear)
• in neutral thermal conditions

Practical lifting capacity: influencing factors

Effective lifting capacity impacted by working environment parameters, including (from most important):

• Gap (between the magnet and the metal), as even a very small distance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to paint, corrosion or debris).
• Loading method – catalog parameter refers to detachment vertically. When attempting to slide, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Steel thickness – too thin plate causes magnetic saturation, causing part of the power to be lost to the other side.
• Steel type – mild steel attracts best. Alloy admixtures reduce magnetic permeability and lifting capacity.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the load capacity is reduced by as much as 75%. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.