SM 32x225 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They have stable power, and over nearly 10 years their performance decreases symbolically – ~1% (according to theory),
• They feature excellent resistance to magnetic field loss when exposed to opposing magnetic fields,
• A magnet with a metallic gold surface has an effective appearance,
• Magnets exhibit impressive magnetic induction on the outer layer,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Due to the option of accurate forming and adaptation to specialized needs, NdFeB magnets can be created in a variety of geometric configurations, which increases their versatility,
• Fundamental importance in advanced technology sectors – they are utilized in mass storage devices, electric drive systems, medical equipment, as well as multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Characteristics of disadvantages of neodymium magnets and ways of using them

• At strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (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
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited ability of making nuts in the magnet and complex shapes - preferred is casing - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, if swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, tiny parts of these devices are able to be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what it depends on?

The declared magnet strength concerns the maximum value, recorded under optimal environment, meaning:

• on a block made of mild steel, optimally conducting the magnetic flux
• whose thickness equals approx. 10 mm
• characterized by smoothness
• under conditions of ideal adhesion (surface-to-surface)
• for force applied at a right angle (pull-off, not shear)
• at room temperature

Determinants of lifting force in real conditions

Real force is influenced by working environment parameters, such as (from priority):

• Air gap (betwixt the magnet and the plate), as even a very small clearance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped to the other side.
• Steel grade – ideal substrate is pure iron steel. Hardened steels may generate lower lifting capacity.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases field saturation. Uneven metal weaken the grip.
• Thermal factor – hot environment weakens pulling force. Too high temperature can permanently damage the magnet.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, however under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.