MW 16x4 / N38 - cylindrical magnet

Pros and cons of rare earth magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (in laboratory conditions),
• Magnets perfectly resist against loss of magnetization caused by external fields,
• In other words, due to the shiny finish of silver, the element gains a professional look,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of exact creating as well as adjusting to atypical conditions,
• Wide application in high-tech industry – they are commonly used in mass storage devices, electric drive systems, advanced medical instruments, also complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in realizing threads and complex shapes in magnets, we propose using cover - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, tiny parts of these products are able to be problematic in diagnostics medical when they are in the body.
• With budget limitations the cost of neodymium magnets is a challenge,

Best holding force of the magnet in ideal parameters – what affects it?

Information about lifting capacity was defined for optimal configuration, including:

• with the application of a sheet made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of min. 10 mm to avoid saturation
• with an polished touching surface
• without any clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

In practice, the actual lifting capacity depends on many variables, ranked from most significant:

• Air gap (between the magnet and the plate), as even a tiny clearance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to paint, rust or debris).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Steel thickness – too thin sheet does not accept the full field, causing part of the power to be escaped into the air.
• Material composition – not every steel attracts identically. Alloy additives worsen the attraction effect.
• Surface structure – the more even the surface, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, however under shearing force the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate reduces the load capacity.