SM 18x275 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• They have stable power, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• Neodymium magnets prove to be exceptionally resistant to demagnetization caused by magnetic disturbances,
• The use of an refined coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
• Due to the ability of precise shaping and customization to unique projects, magnetic components can be modeled in a variety of geometric configurations, which expands the range of possible applications,
• Universal use in innovative solutions – they serve a role in computer drives, electric drive systems, advanced medical instruments, also technologically advanced constructions.
• 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 protecting magnets using a steel holder. Such protection not only shields the magnet but also improves its resistance to damage
• When exposed to high temperature, neodymium magnets experience a drop in strength. 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 as well as corrosion.
• We recommend a housing - magnetic holder, due to difficulties in creating threads inside the magnet and complicated forms.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that small components of these devices can disrupt the diagnostic process medical after entering the body.
• Due to complex production process, their price is relatively high,

Detachment force of the magnet in optimal conditions – what it depends on?

The force parameter is a measurement result executed under the following configuration:

• on a base made of structural steel, optimally conducting the magnetic field
• possessing a massiveness of min. 10 mm to ensure full flux closure
• characterized by even structure
• under conditions of no distance (metal-to-metal)
• for force applied at a right angle (in the magnet axis)
• at room temperature

Practical lifting capacity: influencing factors

Please note that the application force may be lower subject to elements below, in order of importance:

• Space between surfaces – every millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Base massiveness – too thin sheet does not accept the full field, causing part of the power to be escaped into the air.
• Chemical composition of the base – mild steel gives the best results. Alloy steels decrease magnetic permeability and holding force.
• Surface quality – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal factor – hot environment reduces pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate decreases the holding force.