AM ucho [M12] - magnetic accessories

Advantages as well as disadvantages of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (according to theory),
• Magnets perfectly defend themselves against loss of magnetization caused by external fields,
• In other words, due to the aesthetic layer of silver, the element becomes visually attractive,
• Neodymium magnets generate maximum magnetic induction on a small area, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures approaching 230°C and above...
• Possibility of custom forming and adjusting to specific needs,
• Universal use in innovative solutions – they are commonly used in magnetic memories, motor assemblies, medical devices, and modern systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets: application proposals

• To avoid cracks under impact, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves 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 durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of producing nuts in the magnet and complex forms - recommended is casing - magnet mounting.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the context of child safety. Additionally, small components of these magnets can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The specified lifting capacity concerns the maximum value, measured under optimal environment, namely:

• with the contact of a sheet made of special test steel, ensuring full magnetic saturation
• possessing a massiveness of min. 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of no distance (surface-to-surface)
• during pulling in a direction vertical to the plane
• at ambient temperature room level

Practical aspects of lifting capacity – factors

Real force is affected by working environment parameters, such as (from priority):

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel type – mild steel gives the best results. Alloy admixtures reduce magnetic permeability and holding force.
• Surface finish – full contact is possible only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Temperature influence – high temperature weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate lowers the holding force.