SM 32x500 [2xM8] / N52 - magnetic separator

Strengths as well as weaknesses of neodymium magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain full power for nearly 10 years – the loss is just ~1% (in theory),
• Neodymium magnets are distinguished by highly resistant to magnetic field loss caused by external interference,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the working part of the magnet turns out to be maximum,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Thanks to versatility in constructing and the ability to customize to client solutions,
• Universal use in high-tech industry – they serve a role in magnetic memories, electric drive systems, medical equipment, and industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing 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 force. Often, when the temperature exceeds 80°C, their strength 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 suggest a housing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complicated shapes.
• Potential hazard resulting from small fragments of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• Due to expensive raw materials, their price exceeds standard values,

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

Breakaway force was defined for optimal configuration, taking into account:

• using a sheet made of mild steel, acting as a ideal flux conductor
• possessing a thickness of minimum 10 mm to avoid saturation
• with a plane cleaned and smooth
• without the slightest clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at standard ambient temperature

Lifting capacity in practice – influencing factors

Real force impacted by working environment parameters, mainly (from most important):

• Space between magnet and steel – every millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the pulling force, often by half at just 0.5 mm.
• Load vector – maximum parameter is obtained only during pulling at a 90° angle. The resistance to sliding of the magnet along the plate is usually many times smaller (approx. 1/5 of the lifting capacity).
• Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field passes through the material instead of generating force.
• Material composition – different alloys reacts the same. High carbon content worsen the attraction effect.
• Smoothness – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the holding force is lower. In addition, even a slight gap {between} the magnet and the plate reduces the holding force.