SM 18x250 [2xM5] / N42 - magnetic separator

Pros as well as cons of NdFeB magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• Their magnetic field is maintained, and after approximately 10 years it decreases only by ~1% (theoretically),
• They feature excellent resistance to magnetism drop as a result of external fields,
• A magnet with a smooth gold surface looks better,
• The surface of neodymium magnets generates a powerful magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Due to the possibility of accurate forming and customization to individualized projects, NdFeB magnets can be created in a broad palette of forms and dimensions, which amplifies use scope,
• Fundamental importance in high-tech industry – they are commonly used in computer drives, brushless drives, advanced medical instruments, as well as technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which makes them useful in miniature devices

Disadvantages of NdFeB magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in realizing nuts and complicated shapes in magnets, we recommend using casing - magnetic mount.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which is particularly important in the context of child health protection. Additionally, small elements of these products can be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what it depends on?

Information about lifting capacity was defined for the most favorable conditions, assuming:

• using a plate made of high-permeability steel, acting as a circuit closing element
• whose thickness is min. 10 mm
• characterized by lack of roughness
• with total lack of distance (no paint)
• during pulling in a direction perpendicular to the plane
• at temperature room level

Lifting capacity in practice – influencing factors

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

• Clearance – the presence of any layer (rust, dirt, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of converting into lifting capacity.
• Chemical composition of the base – low-carbon steel attracts best. Alloy steels decrease magnetic permeability and lifting capacity.
• Surface quality – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Roughness acts like micro-gaps.
• Temperature influence – high temperature reduces magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was determined using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.