SMZR 32x100 / N52 - magnetic separator with handle

Pros as well as cons of rare earth magnets.

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

• They virtually do not lose power, because even after 10 years the performance loss is only ~1% (according to literature),
• They have excellent resistance to weakening of magnetic properties due to external magnetic sources,
• A magnet with a smooth nickel surface looks better,
• Magnets have extremely high magnetic induction on the outer layer,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• In view of the potential of flexible forming and customization to individualized projects, magnetic components can be produced in a wide range of geometric configurations, which increases their versatility,
• Significant place in electronics industry – they are used in HDD drives, electric motors, advanced medical instruments, and other advanced devices.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can break, 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 strength. 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, in case of application outdoors
• Limited ability of creating nuts in the magnet and complicated shapes - recommended is a housing - magnet mounting.
• Possible danger related to microscopic parts of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• With mass production the cost of neodymium magnets is economically unviable,

Maximum lifting force for a neodymium magnet – what contributes to it?

The declared magnet strength represents the maximum value, measured under ideal test conditions, meaning:

• with the application of a yoke made of low-carbon steel, ensuring full magnetic saturation
• whose thickness equals approx. 10 mm
• with an ground touching surface
• without the slightest insulating layer between the magnet and steel
• for force acting at a right angle (in the magnet axis)
• at ambient temperature room level

What influences lifting capacity in practice

In practice, the actual holding force results from several key aspects, presented from the most important:

• Distance (between the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or dirt).
• Load vector – maximum parameter is reached only during pulling at a 90° angle. The force required to slide of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick sheet does not accept the full field, causing part of the power to be escaped into the air.
• Steel type – low-carbon steel gives the best results. Higher carbon content lower magnetic properties and holding force.
• Smoothness – full contact is obtained only on smooth steel. Any scratches and bumps reduce the real contact area, reducing force.
• Temperature – heating the magnet results in weakening of force. It is worth remembering the maximum operating temperature for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the holding force is lower. In addition, even a slight gap {between} the magnet and the plate lowers the holding force.