ZK XLINK 1026 elementów - construction toy

Strengths and weaknesses of neodymium magnets.

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

• They retain full power for around 10 years – the loss is just ~1% (in theory),
• They do not lose their magnetic properties even under strong external field,
• Thanks to the glossy finish, the plating of Ni-Cu-Ni, gold, or silver-plated gives an elegant appearance,
• They show high magnetic induction at the operating surface, which increases their power,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures reaching 230°C and above...
• Possibility of accurate creating as well as optimizing to specific requirements,
• Fundamental importance in modern industrial fields – they serve a role in magnetic memories, electric motors, medical devices, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which allows their use in small systems

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Due to limitations in creating nuts and complex shapes in magnets, we recommend using casing - magnetic mount.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these products can disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum holding power of the magnet – what it depends on?

The lifting capacity listed is a result of laboratory testing executed under the following configuration:

• using a plate made of low-carbon steel, acting as a circuit closing element
• possessing a thickness of minimum 10 mm to avoid saturation
• with an polished contact surface
• under conditions of gap-free contact (surface-to-surface)
• during pulling in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Determinants of lifting force in real conditions

In real-world applications, the real power depends on many variables, ranked from crucial:

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Material composition – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Temperature influence – hot environment weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* 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. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.