SM 32x350 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

Besides their high retention, neodymium magnets are valued for these benefits:

• They retain full power for around 10 years – the loss is just ~1% (according to analyses),
• They feature excellent resistance to magnetism drop when exposed to external magnetic sources,
• A magnet with a metallic nickel surface has an effective appearance,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, enabling functioning at temperatures reaching 230°C and above...
• Possibility of exact modeling and optimizing to specific requirements,
• Wide application in future technologies – they serve a role in HDD drives, electromotive mechanisms, precision medical tools, and industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (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
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing nuts and complicated shapes in magnets, we recommend using cover - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the aspect of protecting the youngest. It is also worth noting that tiny parts of these magnets are able to complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

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

Magnet power was defined for the most favorable conditions, taking into account:

• with the use of a yoke made of low-carbon steel, ensuring maximum field concentration
• with a thickness minimum 10 mm
• with a surface free of scratches
• with direct contact (without coatings)
• during pulling in a direction perpendicular to the mounting surface
• at room temperature

Determinants of lifting force in real conditions

Holding efficiency is influenced by specific conditions, mainly (from priority):

• Air gap (between the magnet and the plate), since even a microscopic distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Loading method – catalog parameter refers to detachment vertically. When attempting to slide, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Plate thickness – too thin steel does not accept the full field, causing part of the power to be escaped into the air.
• Chemical composition of the base – low-carbon steel gives the best results. Higher carbon content decrease magnetic permeability and lifting capacity.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Roughness acts like micro-gaps.
• Thermal factor – hot environment reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, whereas under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.