MW 8x15 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• They do not lose magnetism, even during nearly ten years – the reduction in strength is only ~1% (based on measurements),
• They retain their magnetic properties even under external field action,
• Thanks to the shimmering finish, the surface of nickel, gold, or silver-plated gives an clean appearance,
• Magnets have excellent 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...
• Thanks to freedom in designing and the ability to modify to unusual requirements,
• Key role in future technologies – they find application in mass storage devices, electric drive systems, diagnostic systems, and modern systems.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in miniature devices

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• They oxidize in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• We recommend casing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex shapes.
• Potential hazard resulting from small fragments of magnets pose a threat, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small components of these devices can disrupt the diagnostic process medical when they are in the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Optimal lifting capacity of a neodymium magnet – what affects it?

Holding force of 6.64 kg is a result of laboratory testing performed under the following configuration:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of at least 10 mm to avoid saturation
• characterized by even structure
• without any air gap between the magnet and steel
• under perpendicular force vector (90-degree angle)
• at room temperature

What influences lifting capacity in practice

Bear in mind that the application force will differ depending on the following factors, in order of importance:

• Clearance – existence of foreign body (paint, tape, air) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – mild steel attracts best. Alloy steels reduce magnetic permeability and holding force.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Rough surfaces reduce efficiency.
• Thermal environment – heating the magnet causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate decreases the lifting capacity.