ZM XMAG2 105 elementów - magnetic toy

Pros as well as cons of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose magnetism, even during around 10 years – the decrease in power is only ~1% (theoretically),
• They retain their magnetic properties even under close interference source,
• In other words, due to the glossy surface of silver, the element becomes visually attractive,
• They show high magnetic induction at the operating surface, making them more effective,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to the option of precise molding and adaptation to custom requirements, neodymium magnets can be created in a variety of geometric configurations, which increases their versatility,
• Versatile presence in electronics industry – they are used in hard drives, electric drive systems, precision medical tools, and complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in power. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• We recommend a housing - magnetic mechanism, due to difficulties in realizing nuts inside the magnet and complicated forms.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which gains importance in the context of child health protection. Additionally, small elements of these devices can disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what contributes to it?

The lifting capacity listed is a measurement result executed under specific, ideal conditions:

• using a sheet made of low-carbon steel, functioning as a circuit closing element
• whose thickness reaches at least 10 mm
• with an polished touching surface
• with zero gap (without paint)
• under perpendicular force direction (90-degree angle)
• in neutral thermal conditions

Practical aspects of lifting capacity – factors

In practice, the real power depends on many variables, listed from the most important:

• Distance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Direction of force – maximum parameter is obtained only during perpendicular pulling. The force required to slide of the magnet along the surface is typically several times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Material composition – different alloys attracts identically. High carbon content weaken the attraction effect.
• Surface finish – ideal contact is possible only on smooth steel. Rough texture create air cushions, reducing force.
• Heat – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.