SM 32x325 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of NdFeB magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They do not lose magnetism, even during approximately 10 years – the decrease in strength is only ~1% (theoretically),
• They possess excellent resistance to weakening of magnetic properties as a result of external fields,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to present itself better,
• Magnets are distinguished by very high magnetic induction on the working surface,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Thanks to modularity in forming and the capacity to modify to complex applications,
• Fundamental importance in modern technologies – they are commonly used in mass storage devices, electric motors, medical devices, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which makes them useful in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. 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
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing threads and complicated shapes in magnets, we recommend using cover - magnetic holder.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, small components of these devices are able to complicate diagnosis medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what contributes to it?

The declared magnet strength refers to the limit force, obtained under optimal environment, namely:

• on a base made of structural steel, perfectly concentrating the magnetic field
• whose transverse dimension reaches at least 10 mm
• with an ground contact surface
• with zero gap (no paint)
• during pulling in a direction perpendicular to the mounting surface
• in neutral thermal conditions

Practical lifting capacity: influencing factors

In real-world applications, the real power results from a number of factors, listed from crucial:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – highest force is available only during perpendicular pulling. The shear force of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Metal type – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Surface finish – full contact is obtained only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Thermal factor – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

* Lifting capacity was determined by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. In addition, even a slight gap {between} the magnet and the plate decreases the lifting capacity.