SM 32x200 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They do not lose magnetism, even after nearly ten years – the reduction in strength is only ~1% (based on measurements),
• They maintain their magnetic properties even under close interference source,
• Thanks to the shimmering finish, the surface of Ni-Cu-Ni, gold, or silver gives an visually attractive appearance,
• Magnets are distinguished by maximum magnetic induction on the outer side,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of exact machining and optimizing to specific requirements,
• Significant place in modern technologies – they serve a role in computer drives, electric drive systems, medical devices, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which enables their usage in miniature devices

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop 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 extremely resistant to heat
• They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited possibility of creating threads in the magnet and complex shapes - preferred is casing - mounting mechanism.
• Potential hazard to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child safety. Furthermore, small elements of these devices can be problematic in diagnostics medical when they are in the body.
• 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

Magnetic strength at its maximum – what it depends on?

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

• using a plate made of low-carbon steel, functioning as a circuit closing element
• with a thickness no less than 10 mm
• with an polished touching surface
• under conditions of gap-free contact (metal-to-metal)
• under perpendicular application of breakaway force (90-degree angle)
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

Effective lifting capacity is influenced by working environment parameters, including (from priority):

• Air gap (betwixt the magnet and the metal), because even a very small distance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of generating force.
• Material type – ideal substrate is pure iron steel. Stainless steels may have worse magnetic properties.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.

Magnetic strength at its maximum – what it depends on?

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

• using a plate made of low-carbon steel, functioning as a circuit closing element
• with a thickness no less than 10 mm
• with an polished touching surface
• under conditions of gap-free contact (metal-to-metal)
• under perpendicular application of breakaway force (90-degree angle)
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

Effective lifting capacity is influenced by working environment parameters, including (from priority):

• Air gap (betwixt the magnet and the metal), because even a very small distance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of generating force.
• Material type – ideal substrate is pure iron steel. Stainless steels may have worse magnetic properties.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Temperature influence – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.