SM 25x200 [2xM8] / N52 - magnetic separator

Pros and cons of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over more than ten years their performance decreases symbolically – ~1% (according to theory),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• In other words, due to the shiny finish of gold, the element becomes visually attractive,
• Magnetic induction on the working part of the magnet turns out to be impressive,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Possibility of detailed modeling as well as adapting to atypical needs,
• Significant place in high-tech industry – they are used in hard drives, brushless drives, precision medical tools, also industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in small systems

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution protects the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• 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, in case of application outdoors
• Due to limitations in creating threads and complicated forms in magnets, we recommend using casing - magnetic mechanism.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these devices are able to be problematic in diagnostics medical in case of swallowing.
• With mass production the cost of neodymium magnets is economically unviable,

Maximum lifting force for a neodymium magnet – what affects it?

The lifting capacity listed is a theoretical maximum value conducted under specific, ideal conditions:

• using a base made of mild steel, serving as a magnetic yoke
• with a cross-section minimum 10 mm
• characterized by smoothness
• without any air gap between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at room temperature

Key elements affecting lifting force

Real force is influenced by specific conditions, such as (from priority):

• Distance (betwixt the magnet and the metal), because even a microscopic distance (e.g. 0.5 mm) leads to a reduction in force by up to 50% (this also applies to paint, corrosion or debris).
• Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet limits the attraction force (the magnet "punches through" it).
• Steel grade – the best choice is pure iron steel. Cast iron may generate lower lifting capacity.
• Base smoothness – the smoother and more polished the plate, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
• Temperature influence – hot environment weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under parallel forces the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet’s surface and the plate lowers the holding force.