SM 32x275 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

• They have constant strength, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Neodymium magnets are extremely resistant to demagnetization caused by external interference,
• A magnet with a metallic gold surface has better aesthetics,
• Magnetic induction on the working layer of the magnet remains strong,
• With the right combination of materials, they reach significant thermal stability, enabling operation at or above 230°C (depending on the design),
• Possibility of exact shaping as well as optimizing to complex requirements,
• Key role in modern industrial fields – they are used in data components, electromotive mechanisms, medical devices, and multitasking production systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• At very strong impacts they can crack, therefore we advise placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can lose their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited ability of making nuts in the magnet and complex forms - recommended is a housing - magnet mounting.
• Health risk resulting from small fragments of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. Additionally, tiny parts of these devices are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what contributes to it?

Holding force of 0 kg is a theoretical maximum value conducted under the following configuration:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• with a cross-section of at least 10 mm
• with a plane free of scratches
• with zero gap (without paint)
• for force acting at a right angle (in the magnet axis)
• at standard ambient temperature

Impact of factors on magnetic holding capacity in practice

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

• Gap (betwixt the magnet and the plate), because even a microscopic distance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to paint, corrosion or debris).
• Angle of force application – highest force is obtained only during perpendicular pulling. The resistance to sliding of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Material type – ideal substrate is pure iron steel. Stainless steels may attract less.
• Plate texture – ground elements ensure maximum contact, which increases field saturation. Uneven metal reduce efficiency.
• Thermal conditions – NdFeB sinters have a negative temperature coefficient. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was measured with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the load capacity is reduced by as much as 75%. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the lifting capacity.