UMS 20x8.6x4.5x7 / N38 - conical magnetic holder

Pros as well as cons of rare earth magnets.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They retain attractive force for nearly ten years – the drop is just ~1% (based on simulations),
• They are noted for resistance to demagnetization induced by external disturbances,
• A magnet with a metallic silver surface is more attractive,
• They feature high magnetic induction at the operating surface, which increases their power,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Possibility of detailed creating and modifying to complex requirements,
• Fundamental importance in modern technologies – they are used in mass storage devices, brushless drives, precision medical tools, as well as other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets and ways of using them

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can fracture. We recommend keeping them in a special holder, which not only protects them against impacts but also increases their 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 corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in creating nuts and complex forms in magnets, we recommend using cover - magnetic mount.
• Potential hazard to health – tiny shards of magnets are risky, if swallowed, which becomes key in the context of child safety. Additionally, small elements of these products can complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum magnetic pulling force – what it depends on?

Holding force of 6 kg is a result of laboratory testing performed under the following configuration:

• on a base made of structural steel, effectively closing the magnetic field
• whose transverse dimension equals approx. 10 mm
• characterized by smoothness
• under conditions of gap-free contact (surface-to-surface)
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature approx. 20 degrees Celsius

What influences lifting capacity in practice

It is worth knowing that the working load may be lower influenced by the following factors, in order of importance:

• Distance (between 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).
• Load vector – maximum parameter is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Steel grade – the best choice is pure iron steel. Hardened steels may have worse magnetic properties.
• Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – heating the magnet results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.