UMH 25x8x45 [M5] / N38 - magnetic holder with hook

Advantages as well as disadvantages of neodymium magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (in laboratory conditions),
• They possess excellent resistance to weakening of magnetic properties as a result of opposing magnetic fields,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• 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 shaping and the capacity to customize to unusual requirements,
• Wide application in innovative solutions – they find application in HDD drives, electric drive systems, medical devices, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• Due to limitations in realizing nuts and complicated shapes in magnets, we recommend using casing - magnetic mount.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the context of child health protection. Additionally, small elements of these magnets can be problematic in diagnostics medical when they are in the body.
• With large orders the cost of neodymium magnets can be a barrier,

Highest magnetic holding force – what affects it?

The lifting capacity listed is a result of laboratory testing executed under specific, ideal conditions:

• on a base made of structural steel, effectively closing the magnetic flux
• possessing a massiveness of minimum 10 mm to avoid saturation
• with a plane cleaned and smooth
• without the slightest insulating layer between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at temperature room level

Lifting capacity in practice – influencing factors

It is worth knowing that the application force will differ subject to elements below, starting with the most relevant:

• Clearance – existence of any layer (rust, tape, air) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet holds much less (often approx. 20-30% of nominal force).
• Base massiveness – too thin steel does not close the flux, causing part of the power to be escaped to the other side.
• Steel grade – the best choice is high-permeability steel. Cast iron may attract less.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Temperature influence – hot environment weakens pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied 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 reduces the holding force.