MW 38x3.5 / N38 - cylindrical magnet

Advantages as well as disadvantages of NdFeB magnets.

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

• They have unchanged lifting capacity, and over nearly 10 years their attraction force decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under strong external field,
• By applying a lustrous coating of nickel, the element gains an professional look,
• They feature high magnetic induction at the operating surface, making them more effective,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures approaching 230°C and above...
• Thanks to modularity in constructing and the capacity to adapt to unusual requirements,
• Wide application in innovative solutions – they are commonly used in mass storage devices, electric motors, medical devices, as well as multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which enables their usage in miniature devices

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength 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 those in rubber or plastics, which prevent oxidation as well as corrosion.
• We suggest casing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex shapes.
• Possible danger to health – tiny shards of magnets are risky, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these devices can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

The declared magnet strength represents the limit force, obtained under laboratory conditions, namely:

• using a plate made of high-permeability steel, serving as a circuit closing element
• whose thickness reaches at least 10 mm
• characterized by even structure
• under conditions of gap-free contact (surface-to-surface)
• for force acting at a right angle (pull-off, not shear)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

In real-world applications, the actual holding force depends on several key aspects, presented from crucial:

• Distance – the presence of foreign body (rust, tape, gap) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Base massiveness – insufficiently thick sheet does not accept the full field, causing part of the power to be lost to the other side.
• Steel grade – ideal substrate is pure iron steel. Hardened steels may generate lower lifting capacity.
• Surface quality – the more even the surface, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate lowers the lifting capacity.