AM ucho [M12] - magnetic accessories

Pros as well as cons of NdFeB magnets.

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

• They have unchanged lifting capacity, and over around ten years their performance decreases symbolically – ~1% (according to theory),
• They do not lose their magnetic properties even under external field action,
• In other words, due to the reflective finish of silver, the element looks attractive,
• Neodymium magnets ensure maximum magnetic induction on a small area, which increases force concentration,
• With the right combination of magnetic alloys, they reach significant thermal stability, enabling operation at or above 230°C (depending on the form),
• Possibility of exact forming as well as adjusting to concrete conditions,
• Significant place in modern technologies – they serve a role in magnetic memories, motor assemblies, precision medical tools, and other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, 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 protects 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 durability 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 resistant to moisture, in case of application outdoors
• We recommend casing - magnetic mount, due to difficulties in realizing threads inside the magnet and complex shapes.
• Possible danger resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the context of child safety. It is also worth noting that small elements of these products can be problematic in diagnostics medical when they are in the body.
• With mass production the cost of neodymium magnets is a challenge,

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

Holding force of 480 kg is a result of laboratory testing executed under the following configuration:

• on a block made of mild steel, optimally conducting the magnetic flux
• possessing a massiveness of min. 10 mm to avoid saturation
• with an polished contact surface
• under conditions of ideal adhesion (metal-to-metal)
• during pulling in a direction perpendicular to the mounting surface
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

Effective lifting capacity is affected by working environment parameters, such as (from most important):

• Air gap (betwixt the magnet and the plate), since even a tiny clearance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to varnish, corrosion or dirt).
• Angle of force application – maximum parameter is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – mild steel gives the best results. Alloy steels decrease magnetic permeability and lifting capacity.
• Surface quality – the smoother and more polished the plate, the better the adhesion and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – heating the magnet causes a temporary drop of force. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.