SM 25x225 [2xM8] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• Their power is maintained, and after around 10 years it drops only by ~1% (theoretically),
• Neodymium magnets are distinguished by highly resistant to demagnetization caused by external magnetic fields,
• Thanks to the elegant finish, the layer of nickel, gold, or silver gives an visually attractive appearance,
• They show high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• In view of the option of flexible forming and adaptation to unique projects, neodymium magnets can be modeled in a wide range of geometric configurations, which makes them more universal,
• Wide application in innovative solutions – they serve a role in HDD drives, drive modules, medical devices, as well as other advanced devices.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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 very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• We suggest cover - magnetic mount, due to difficulties in producing threads inside the magnet and complicated shapes.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small components of these magnets can complicate diagnosis medical in case of swallowing.
• With large orders the cost of neodymium magnets is economically unviable,

Maximum holding power of the magnet – what contributes to it?

The specified lifting capacity represents the maximum value, obtained under ideal test conditions, namely:

• on a block made of mild steel, perfectly concentrating the magnetic flux
• with a cross-section no less than 10 mm
• characterized by smoothness
• under conditions of ideal adhesion (surface-to-surface)
• under axial force vector (90-degree angle)
• at conditions approx. 20°C

Lifting capacity in real conditions – factors

Bear in mind that the magnet holding may be lower depending on elements below, in order of importance:

• Distance – the presence of foreign body (rust, dirt, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Material type – the best choice is pure iron steel. Stainless steels may have worse magnetic properties.
• Smoothness – full contact is obtained only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Operating temperature – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined by applying a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet and the plate decreases the load capacity.