SM 32x425 [2xM8] / N52 - magnetic separator

Strengths and weaknesses of neodymium magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They do not lose their magnetic properties even under strong external field,
• In other words, due to the smooth layer of silver, the element is aesthetically pleasing,
• Magnets are distinguished by huge magnetic induction on the active area,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of exact modeling as well as adapting to individual requirements,
• Fundamental importance in electronics industry – they are utilized in mass storage devices, electric motors, advanced medical instruments, and multitasking production systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Cons of neodymium magnets: application proposals

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
• Limited possibility of making nuts in the magnet and complicated forms - recommended is casing - mounting mechanism.
• Possible danger to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the context of child safety. Additionally, small elements of these magnets can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which hinders application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

Magnet power is the result of a measurement for the most favorable conditions, assuming:

• on a base made of structural steel, perfectly concentrating the magnetic flux
• with a thickness minimum 10 mm
• with a plane perfectly flat
• with total lack of distance (without impurities)
• during pulling in a direction vertical to the mounting surface
• at standard ambient temperature

What influences lifting capacity in practice

During everyday use, the actual lifting capacity results from several key aspects, ranked from the most important:

• Clearance – existence of any layer (paint, dirt, gap) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Steel grade – ideal substrate is pure iron steel. Cast iron may have worse magnetic properties.
• Base smoothness – the more even the surface, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal environment – heating the magnet results in weakening of force. Check the thermal limit for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate decreases the holding force.