SM 32x200 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of neodymium magnets.

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

• Their strength is maintained, and after around 10 years it decreases only by ~1% (according to research),
• They maintain their magnetic properties even under close interference source,
• Thanks to the elegant finish, the layer of Ni-Cu-Ni, gold-plated, or silver gives an elegant appearance,
• They feature high magnetic induction at the operating surface, making them more effective,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• In view of the possibility of free molding and customization to individualized projects, neodymium magnets can be manufactured in a broad palette of shapes and sizes, which expands the range of possible applications,
• Fundamental importance in modern industrial fields – they are commonly used in HDD drives, electromotive mechanisms, advanced medical instruments, and other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Drawbacks and weaknesses of neodymium magnets and ways of using them

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size and 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
• Due to limitations in producing threads and complicated shapes in magnets, we propose using a housing - magnetic mechanism.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the context of child health protection. Additionally, small elements of these products are able to disrupt the diagnostic process 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

Optimal lifting capacity of a neodymium magnet – what contributes to it?

Breakaway force was defined for ideal contact conditions, assuming:

• with the use of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with a surface cleaned and smooth
• without any insulating layer between the magnet and steel
• during pulling in a direction vertical to the mounting surface
• at temperature room level

Lifting capacity in real conditions – factors

Effective lifting capacity impacted by specific conditions, including (from priority):

• Clearance – existence of foreign body (paint, dirt, air) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When slipping, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
• Steel thickness – too thin steel does not accept the full field, causing part of the flux to be lost into the air.
• Plate material – low-carbon steel gives the best results. Alloy steels decrease magnetic properties and lifting capacity.
• Surface structure – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Roughness creates an air distance.
• Temperature – heating the magnet results in weakening of force. Check the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.