SM 32x150 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of rare earth magnets.

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

• They retain full power for almost 10 years – the loss is just ~1% (in theory),
• They are extremely resistant to demagnetization induced by external disturbances,
• By using a reflective coating of gold, the element has an proper look,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
• Due to the possibility of precise molding and adaptation to individualized solutions, NdFeB magnets can be produced in a broad palette of forms and dimensions, which makes them more universal,
• Wide application in high-tech industry – they are commonly used in mass storage devices, motor assemblies, diagnostic systems, as well as multitasking production systems.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets: weaknesses and usage proposals

• At very strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience 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
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing nuts and complex forms in magnets, we recommend using casing - magnetic holder.
• Possible danger to health – tiny shards of magnets pose a threat, in case of ingestion, which gains importance in the aspect of protecting the youngest. It is also worth noting that tiny parts of these devices are able to be problematic in diagnostics medical in case of swallowing.
• 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 affects it?

The lifting capacity listed is a theoretical maximum value performed under the following configuration:

• using a base made of high-permeability steel, serving as a ideal flux conductor
• whose thickness is min. 10 mm
• characterized by even structure
• under conditions of no distance (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at standard ambient temperature

Determinants of lifting force in real conditions

Please note that the application force will differ influenced by the following factors, in order of importance:

• Clearance – the presence of any layer (rust, dirt, air) acts as an insulator, which reduces power rapidly (even by 50% at 0.5 mm).
• Loading method – declared lifting capacity refers to detachment vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Material type – the best choice is high-permeability steel. Stainless steels may have worse magnetic properties.
• Base smoothness – the smoother and more polished the plate, the better the adhesion and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate reduces the holding force.