MW 5x30 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They do not lose magnetism, even during nearly ten years – the reduction in lifting capacity is only ~1% (according to tests),
• They are extremely resistant to demagnetization induced by external disturbances,
• A magnet with a shiny nickel surface has an effective appearance,
• Magnets are characterized by extremely high magnetic induction on the working surface,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to flexibility in forming and the capacity to modify to unusual requirements,
• Fundamental importance in electronics industry – they are commonly used in data components, electromotive mechanisms, precision medical tools, also complex engineering applications.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their strength 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
• 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 secure oxidation and corrosion.
• Limited ability of making threads in the magnet and complicated forms - preferred is casing - magnet mounting.
• Possible danger resulting from small fragments of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, tiny parts of these magnets can complicate diagnosis medical after entering the body.
• Due to complex production process, their price exceeds standard values,

Optimal lifting capacity of a neodymium magnet – what contributes to it?

Holding force of 8.29 kg is a measurement result conducted under standard conditions:

• on a plate made of structural steel, effectively closing the magnetic flux
• with a cross-section of at least 10 mm
• characterized by smoothness
• under conditions of gap-free contact (surface-to-surface)
• during detachment in a direction perpendicular to the mounting surface
• at room temperature

Key elements affecting lifting force

Bear in mind that the application force may be lower influenced by the following factors, in order of importance:

• Distance – the presence of foreign body (paint, tape, gap) acts as an insulator, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick plate does not accept the full field, causing part of the flux to be wasted into the air.
• Material type – the best choice is pure iron steel. Hardened steels may attract less.
• Surface structure – the more even the surface, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.