UMH 75x18x68 [M8] / N38 - magnetic holder with hook

Advantages as well as disadvantages of rare earth magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• Magnets perfectly defend themselves against loss of magnetization caused by foreign field sources,
• Thanks to the smooth finish, the plating of nickel, gold, or silver-plated gives an professional appearance,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures approaching 230°C and above...
• Thanks to the possibility of flexible shaping and customization to unique projects, magnetic components can be produced in a variety of forms and dimensions, which expands the range of possible applications,
• Versatile presence in advanced technology sectors – they are used in mass storage devices, electromotive mechanisms, medical equipment, and technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in miniature devices

Disadvantages of NdFeB magnets:

• At strong impacts they can break, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• They rust in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We suggest casing - magnetic mount, due to difficulties in realizing nuts inside the magnet and complicated shapes.
• Health risk to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the context of child safety. Furthermore, small components of these magnets can complicate diagnosis medical in case of swallowing.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting force for a neodymium magnet – what it depends on?

The force parameter is a result of laboratory testing performed under specific, ideal conditions:

• using a plate made of low-carbon steel, serving as a ideal flux conductor
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• without any clearance between the magnet and steel
• under axial force direction (90-degree angle)
• in neutral thermal conditions

Lifting capacity in real conditions – factors

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

• Distance – existence of any layer (paint, dirt, air) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, 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 generating force.
• Metal type – different alloys attracts identically. High carbon content weaken the interaction with the magnet.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet and the plate lowers the lifting capacity.