SM 25x150 [2xM8] / N42 - magnetic separator

Pros and cons of rare earth magnets.

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

• They retain full power for almost 10 years – the loss is just ~1% (based on simulations),
• They do not lose their magnetic properties even under external field action,
• By covering with a lustrous layer of silver, the element has an proper look,
• Neodymium magnets create maximum magnetic induction on a small area, which increases force concentration,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Due to the possibility of flexible molding and adaptation to unique projects, neodymium magnets can be produced in a broad palette of shapes and sizes, which makes them more universal,
• Key role in electronics industry – they are commonly used in mass storage devices, motor assemblies, advanced medical instruments, and modern systems.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing 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 suffer a drop in power. Often, when the temperature exceeds 80°C, their power 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
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Limited possibility of producing threads in the magnet and complex shapes - preferred is casing - magnetic holder.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which is particularly important in the context of child health protection. It is also worth noting that small elements of these products are able to complicate diagnosis 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

Maximum holding power of the magnet – what affects it?

Breakaway force is the result of a measurement for the most favorable conditions, taking into account:

• with the use of a yoke made of low-carbon steel, guaranteeing full magnetic saturation
• possessing a thickness of min. 10 mm to avoid saturation
• characterized by even structure
• under conditions of gap-free contact (metal-to-metal)
• under axial force direction (90-degree angle)
• in stable room temperature

Practical lifting capacity: influencing factors

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

• Clearance – the presence of foreign body (paint, tape, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of converting into lifting capacity.
• Material type – the best choice is high-permeability steel. Cast iron may attract less.
• Plate texture – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces reduce efficiency.
• Thermal factor – hot environment reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was assessed using a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 5 times. Moreover, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.