SM 25x250 [2xM8] / N42 - magnetic separator

Advantages as well as disadvantages of rare earth magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• Their strength is maintained, and after around 10 years it decreases only by ~1% (theoretically),
• They possess excellent resistance to magnetic field loss as a result of opposing magnetic fields,
• A magnet with a shiny gold surface has better aesthetics,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of detailed shaping as well as adapting to concrete conditions,
• Significant place in modern industrial fields – they serve a role in computer drives, electric drive systems, advanced medical instruments, as well as complex engineering applications.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only protects the magnet but also improves its resistance to damage
• 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 extremely resistant to heat
• They rust in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complicated shapes in magnets, we propose using casing - magnetic mount.
• Potential hazard resulting from small fragments of magnets can be dangerous, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these products are able to disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Breakaway strength of the magnet in ideal conditions – what it depends on?

The lifting capacity listed is a result of laboratory testing executed under the following configuration:

• with the application of a yoke made of low-carbon steel, guaranteeing maximum field concentration
• possessing a massiveness of at least 10 mm to ensure full flux closure
• characterized by lack of roughness
• under conditions of ideal adhesion (metal-to-metal)
• for force acting at a right angle (pull-off, not shear)
• at room temperature

Determinants of practical lifting force of a magnet

It is worth knowing that the magnet holding will differ subject to elements below, in order of importance:

• Air gap (betwixt the magnet and the plate), since even a tiny distance (e.g. 0.5 mm) results in a reduction in lifting capacity by up to 50% (this also applies to varnish, rust or dirt).
• Force direction – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Element thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface finish – ideal contact is obtained only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, in contrast under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.