MP 22x6x10 / N38 - ring magnet

Pros and cons of NdFeB magnets.

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

• They do not lose strength, even over approximately ten years – the drop in lifting capacity is only ~1% (theoretically),
• They do not lose their magnetic properties even under strong external field,
• In other words, due to the metallic finish of nickel, the element is aesthetically pleasing,
• They show high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Possibility of accurate creating as well as optimizing to atypical needs,
• Universal use in advanced technology sectors – they serve a role in mass storage devices, electromotive mechanisms, diagnostic systems, and other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Limited ability of creating nuts in the magnet and complicated shapes - preferred is casing - mounting mechanism.
• Potential hazard to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, small elements of these devices can disrupt the diagnostic process medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what affects it?

The force parameter is a theoretical maximum value executed under the following configuration:

• on a plate made of mild steel, perfectly concentrating the magnetic flux
• with a thickness of at least 10 mm
• with an polished touching surface
• without the slightest air gap between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• in neutral thermal conditions

Practical lifting capacity: influencing factors

It is worth knowing that the working load may be lower subject to the following factors, in order of importance:

• Air gap (betwixt the magnet and the plate), as even a tiny distance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Direction of force – highest force is available only during perpendicular pulling. The shear force of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel attracts best. Higher carbon content lower magnetic properties and lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which increases force. Rough surfaces weaken the grip.
• Heat – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).

* Lifting capacity was assessed by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.