SM 25x125 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

Apart from their superior magnetic energy, neodymium magnets have these key benefits:

• They retain attractive force for around ten years – the loss is just ~1% (in theory),
• They do not lose their magnetic properties even under external field action,
• By using a decorative coating of gold, the element has an professional look,
• Magnets have excellent magnetic induction on the surface,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Possibility of detailed modeling and modifying to specific conditions,
• Fundamental importance in future technologies – they are utilized in mass storage devices, drive modules, medical devices, as well as complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only protects them against impacts but also increases their durability
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power 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 rust. Therefore during using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of creating threads in the magnet and complex forms - preferred is cover - magnet mounting.
• Potential hazard to health – tiny shards of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child health protection. Additionally, tiny parts of these devices can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum lifting capacity of the magnet – what it depends on?

The lifting capacity listed is a theoretical maximum value conducted under standard conditions:

• using a plate made of high-permeability steel, serving as a ideal flux conductor
• with a thickness minimum 10 mm
• with a surface perfectly flat
• with total lack of distance (without paint)
• for force acting at a right angle (pull-off, not shear)
• at standard ambient temperature

Practical aspects of lifting capacity – factors

It is worth knowing that the working load may be lower influenced by elements below, in order of importance:

• Distance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Load vector – highest force is obtained only during pulling at a 90° angle. The shear force of the magnet along the surface is usually many times lower (approx. 1/5 of the lifting capacity).
• Base massiveness – insufficiently thick plate does not close the flux, causing part of the power to be lost into the air.
• Material composition – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Surface condition – smooth surfaces ensure maximum contact, which improves force. Uneven metal reduce efficiency.
• Temperature influence – high temperature weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet and the plate reduces the lifting capacity.