SM 25x250 [2xM8] / N52 - magnetic separator

Pros as well as cons of NdFeB magnets.

Besides their tremendous pulling force, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (in laboratory conditions),
• Neodymium magnets are characterized by exceptionally resistant to loss of magnetic properties caused by external interference,
• The use of an refined finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Neodymium magnets ensure maximum magnetic induction on a contact point, which increases force concentration,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for functioning at temperatures reaching 230°C and above...
• Thanks to freedom in shaping and the ability to adapt to complex applications,
• Key role in modern industrial fields – they serve a role in mass storage devices, drive modules, precision medical tools, and other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (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
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• We suggest cover - magnetic mount, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets are risky, if swallowed, which becomes key in the context of child safety. Additionally, small components of these magnets are able to complicate diagnosis medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Highest magnetic holding force – what affects it?

The force parameter is a theoretical maximum value performed under specific, ideal conditions:

• using a base made of low-carbon steel, functioning as a circuit closing element
• whose thickness is min. 10 mm
• characterized by lack of roughness
• without the slightest clearance between the magnet and steel
• under axial force vector (90-degree angle)
• at room temperature

Determinants of practical lifting force of a magnet

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

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to pulling vertically. When slipping, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is high-permeability steel. Stainless steels may have worse magnetic properties.
• Smoothness – full contact is obtained only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Temperature – temperature increase causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.