SM 32x250 [2xM8] / N52 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They do not lose power, even during around 10 years – the drop in power is only ~1% (based on measurements),
• Magnets very well defend themselves against loss of magnetization caused by ambient magnetic noise,
• By using a shiny coating of silver, the element presents an elegant look,
• Magnetic induction on the working part of the magnet is strong,
• 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 individual shaping as well as modifying to individual requirements,
• Huge importance in future technologies – they find application in HDD drives, motor assemblies, diagnostic systems, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which allows their use in small systems

Characteristics of disadvantages of neodymium magnets: application proposals

• At very strong impacts they can crack, therefore we advise placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We suggest a housing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex forms.
• Potential hazard related to microscopic parts of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Furthermore, small components of these devices are able to disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The specified lifting capacity refers to the maximum value, obtained under laboratory conditions, specifically:

• using a plate made of low-carbon steel, functioning as a magnetic yoke
• whose transverse dimension is min. 10 mm
• with a plane free of scratches
• under conditions of gap-free contact (metal-to-metal)
• during pulling in a direction vertical to the mounting surface
• at ambient temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

In practice, the actual holding force depends on a number of factors, ranked from crucial:

• Air gap (betwixt the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) results in a decrease in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Loading method – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits much less (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 converting into lifting capacity.
• Chemical composition of the base – mild steel gives the best results. Alloy steels decrease magnetic properties and lifting capacity.
• Surface finish – ideal contact is possible only on polished steel. Rough texture create air cushions, weakening the magnet.
• Thermal environment – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate decreases the load capacity.