SM 32x125 [2xM8] / N52 - magnetic separator

Pros as well as cons of rare earth magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They retain attractive force for around 10 years – the loss is just ~1% (based on simulations),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• The use of an metallic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Neodymium magnets create maximum magnetic induction on a small area, which allows for strong attraction,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• Possibility of precise shaping as well as optimizing to defined applications,
• Universal use in electronics industry – they serve a role in mass storage devices, brushless drives, medical equipment, as well as technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in small systems

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• 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, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Limited ability of creating nuts in the magnet and complex forms - preferred is casing - mounting mechanism.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Furthermore, small components of these products can be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what affects it?

The force parameter is a result of laboratory testing conducted under specific, ideal conditions:

• on a base made of structural steel, effectively closing the magnetic field
• with a cross-section no less than 10 mm
• with a surface free of scratches
• under conditions of gap-free contact (metal-to-metal)
• during pulling in a direction perpendicular to the plane
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

Bear in mind that the application force will differ depending on the following factors, starting with the most relevant:

• Distance – existence of any layer (paint, tape, gap) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
• Angle of force application – maximum parameter is obtained only during perpendicular pulling. The shear force of the magnet along the surface is usually many times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – insufficiently thick steel does not accept the full field, causing part of the flux to be wasted into the air.
• Material type – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Surface quality – the more even the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Temperature influence – hot environment weakens pulling force. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was measured with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.