ZM XMAG2 105 elementów - magnetic toy

Advantages and disadvantages of neodymium magnets.

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

• Their magnetic field is maintained, and after approximately ten years it drops only by ~1% (theoretically),
• They are extremely resistant to demagnetization induced by external field influence,
• Thanks to the smooth finish, the surface of nickel, gold-plated, or silver-plated gives an clean appearance,
• Neodymium magnets generate maximum magnetic induction on a contact point, which allows for strong attraction,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures approaching 230°C and above...
• Considering the ability of accurate molding and adaptation to unique requirements, NdFeB magnets can be modeled in a variety of shapes and sizes, which amplifies use scope,
• Fundamental importance in modern technologies – they serve a role in mass storage devices, electric drive systems, advanced medical instruments, also other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At very strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• 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, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of creating nuts in the magnet and complex forms - recommended is a housing - magnet mounting.
• Health risk to health – tiny shards of magnets pose a threat, when accidentally swallowed, which is particularly important in the context of child health protection. Furthermore, small components of these magnets are able to complicate diagnosis medical after entering the body.
• With mass production the cost of neodymium magnets is a challenge,

Optimal lifting capacity of a neodymium magnet – what it depends on?

Breakaway force was determined for the most favorable conditions, taking into account:

• on a plate made of structural steel, optimally conducting the magnetic field
• possessing a thickness of minimum 10 mm to ensure full flux closure
• with a surface free of scratches
• with direct contact (no coatings)
• during pulling in a direction vertical to the plane
• at room temperature

Practical lifting capacity: influencing factors

It is worth knowing that the working load may be lower influenced by the following factors, starting with the most relevant:

• Distance – the presence of foreign body (rust, dirt, air) acts as an insulator, which lowers power steeply (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Plate thickness – too thin steel does not accept the full field, causing part of the power to be escaped into the air.
• Material type – the best choice is pure iron steel. Cast iron may have worse magnetic properties.
• Surface structure – the more even the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.