SM 32x275 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of neodymium magnets.

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

• They retain magnetic properties for almost ten years – the drop is just ~1% (according to analyses),
• Neodymium magnets prove to be highly resistant to demagnetization caused by magnetic disturbances,
• The use of an elegant coating of noble metals (nickel, gold, silver) causes the element to present itself better,
• They are known for high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• In view of the potential of accurate forming and adaptation to custom solutions, NdFeB magnets can be manufactured in a broad palette of geometric configurations, which increases their versatility,
• Huge importance in modern industrial fields – they are commonly used in HDD drives, brushless drives, medical equipment, and modern systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating nuts and complex shapes in magnets, we recommend using casing - magnetic holder.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child health protection. It is also worth noting that tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• With large orders the cost of neodymium magnets can be a barrier,

Highest magnetic holding force – what affects it?

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

• with the use of a yoke made of special test steel, ensuring full magnetic saturation
• possessing a massiveness of minimum 10 mm to avoid saturation
• with a plane perfectly flat
• without the slightest insulating layer between the magnet and steel
• under vertical force direction (90-degree angle)
• in stable room temperature

Practical lifting capacity: influencing factors

In real-world applications, the actual holding force depends on several key aspects, ranked from the most important:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Steel type – low-carbon steel gives the best results. Alloy steels reduce magnetic properties and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Rough surfaces weaken the grip.
• Thermal factor – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity was determined with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.