SM 32x375 [2xM8] / N52 - magnetic separator

Pros and cons of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They do not lose magnetism, even during around ten years – the decrease in lifting capacity is only ~1% (according to tests),
• Magnets very well resist against loss of magnetization caused by external fields,
• A magnet with a metallic gold surface is more attractive,
• Magnetic induction on the surface of the magnet is exceptional,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to modularity in forming and the ability to modify to complex applications,
• Significant place in future technologies – they are commonly used in HDD drives, electric drive systems, advanced medical instruments, and modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only secures them against impacts but also raises their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and 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
• 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 as well as corrosion.
• Due to limitations in producing threads and complicated shapes in magnets, we propose using a housing - magnetic holder.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. It is also worth noting that small components of these products can be problematic in diagnostics medical after entering the body.
• Due to expensive raw materials, their price is relatively high,

Magnetic strength at its maximum – what it depends on?

Magnet power is the result of a measurement for optimal configuration, assuming:

• using a base made of high-permeability steel, serving as a circuit closing element
• with a cross-section minimum 10 mm
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• under perpendicular force direction (90-degree angle)
• in neutral thermal conditions

Determinants of practical lifting force of a magnet

It is worth knowing that the application force may be lower subject to elements below, starting with the most relevant:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel grade – ideal substrate is high-permeability steel. Hardened steels may attract less.
• Surface finish – ideal contact is obtained only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Thermal factor – high temperature weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.