SMZR 25x225 / N52 - magnetic separator with handle

Pros as well as cons of rare earth magnets.

Apart from their notable power, neodymium magnets have these key benefits:

• Their power is durable, and after around ten years it decreases only by ~1% (according to research),
• Neodymium magnets prove to be exceptionally resistant to demagnetization caused by magnetic disturbances,
• A magnet with a metallic gold surface looks better,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to flexibility in constructing and the capacity to customize to complex applications,
• Significant place in future technologies – they find application in computer drives, electric drive systems, diagnostic systems, as well as other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets decrease their power 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
• They oxidize in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• We recommend cover - magnetic mechanism, due to difficulties in producing threads inside the magnet and complex shapes.
• Potential hazard resulting from small fragments of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these devices can disrupt the diagnostic process medical in case of swallowing.
• Due to complex production process, their price exceeds standard values,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The load parameter shown concerns the limit force, obtained under laboratory conditions, specifically:

• using a plate made of low-carbon steel, serving as a magnetic yoke
• possessing a thickness of at least 10 mm to ensure full flux closure
• characterized by lack of roughness
• with total lack of distance (no impurities)
• during pulling in a direction perpendicular to the plane
• in neutral thermal conditions

Practical lifting capacity: influencing factors

Effective lifting capacity impacted by specific conditions, such as (from most important):

• Gap (between the magnet and the metal), since even a microscopic distance (e.g. 0.5 mm) can cause a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – highest force is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Material composition – different alloys reacts the same. High carbon content worsen the attraction effect.
• Surface finish – full contact is obtained only on polished steel. Rough texture reduce the real contact area, weakening the magnet.
• Thermal factor – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed by applying a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet and the plate reduces the holding force.