MP 62x42x25 / N38 - ring magnet

Strengths as well as weaknesses of neodymium magnets.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They do not lose strength, even over approximately ten years – the drop in strength is only ~1% (based on measurements),
• They are noted for resistance to demagnetization induced by external field influence,
• By applying a smooth layer of silver, the element gains an elegant look,
• Magnetic induction on the working part of the magnet is maximum,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, enabling action at temperatures reaching 230°C and above...
• Thanks to the potential of flexible shaping and adaptation to individualized requirements, neodymium magnets can be produced in a broad palette of geometric configurations, which increases their versatility,
• Huge importance in innovative solutions – they find application in data components, electromotive mechanisms, advanced medical instruments, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

What to avoid - cons of neodymium magnets: application proposals

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complicated forms in magnets, we propose using a housing - magnetic mount.
• Health risk resulting from small fragments of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that small components of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Highest magnetic holding force – what contributes to it?

The force parameter is a result of laboratory testing executed under specific, ideal conditions:

• using a plate made of mild steel, functioning as a circuit closing element
• whose thickness equals approx. 10 mm
• with a plane free of scratches
• without any clearance between the magnet and steel
• under axial force direction (90-degree angle)
• in stable room temperature

Lifting capacity in practice – influencing factors

Bear in mind that the application force may be lower influenced by elements below, starting with the most relevant:

• Space between magnet and steel – every millimeter of separation (caused e.g. by veneer or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Material composition – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Temperature – temperature increase causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Lifting capacity was measured with the use of a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.