SM 32x375 [2xM8] / N52 - magnetic separator

Pros and cons of NdFeB magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They do not lose power, even after around ten years – the decrease in strength is only ~1% (theoretically),
• They show high resistance to demagnetization induced by external disturbances,
• A magnet with a smooth nickel surface is more attractive,
• Neodymium magnets generate maximum magnetic induction on a their surface, which ensures high operational effectiveness,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• In view of the option of accurate forming and customization to custom solutions, NdFeB magnets can be modeled in a wide range of shapes and sizes, which increases their versatility,
• Huge importance in future technologies – they are commonly used in hard drives, electromotive mechanisms, precision medical tools, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which allows their use in small systems

Characteristics of disadvantages of neodymium magnets: application proposals

• Brittleness is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a strong case, which not only protects them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of making threads in the magnet and complex forms - recommended is casing - mounting mechanism.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the context of child health protection. Furthermore, small elements of these products can disrupt the diagnostic process medical when they are in the body.
• Due to expensive raw materials, their price is higher than average,

Maximum magnetic pulling force – what contributes to it?

The lifting capacity listed is a result of laboratory testing executed under the following configuration:

• using a base made of high-permeability steel, serving as a magnetic yoke
• possessing a thickness of at least 10 mm to ensure full flux closure
• characterized by even structure
• without any insulating layer between the magnet and steel
• under axial application of breakaway force (90-degree angle)
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

During everyday use, the real power results from many variables, listed from crucial:

• Distance (betwixt the magnet and the metal), since even a very small clearance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to varnish, rust or debris).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of maximum force).
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Metal type – different alloys reacts the same. High carbon content weaken the attraction effect.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Thermal environment – temperature increase causes a temporary drop of induction. It is worth remembering the thermal limit for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.