MPL 20x20x20 / N38 - lamellar magnet

Strengths as well as weaknesses of rare earth magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They do not lose power, even after around 10 years – the reduction in lifting capacity is only ~1% (theoretically),
• They maintain their magnetic properties even under external field action,
• By using a shiny coating of nickel, the element gains an elegant look,
• Neodymium magnets achieve maximum magnetic induction on a small area, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to freedom in constructing and the capacity to modify to unusual requirements,
• Universal use in modern industrial fields – they find application in computer drives, drive modules, advanced medical instruments, as well as technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We recommend keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of creating nuts in the magnet and complicated shapes - preferred is cover - magnet mounting.
• Potential hazard to health – tiny shards of magnets can be dangerous, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. It is also worth noting that small elements of these devices are able to be problematic in diagnostics 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

Detachment force of the magnet in optimal conditions – what contributes to it?

Information about lifting capacity was determined for the most favorable conditions, including:

• with the application of a yoke made of low-carbon steel, ensuring maximum field concentration
• whose thickness reaches at least 10 mm
• with an polished touching surface
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the plane
• at temperature room level

Determinants of lifting force in real conditions

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

• Gap (between the magnet and the metal), since even a microscopic distance (e.g. 0.5 mm) can cause a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Load vector – maximum parameter is available only during pulling at a 90° angle. The shear force 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 penetrates through instead of generating force.
• Metal type – different alloys reacts the same. Alloy additives weaken the attraction effect.
• Surface finish – full contact is possible only on smooth steel. Rough texture reduce the real contact area, reducing force.
• Temperature – heating the magnet causes a temporary drop of force. 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, however under attempts to slide the magnet the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.