SM 32x275 [2xM8] / N42 - magnetic separator

Advantages and disadvantages of rare earth magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• They do not lose magnetism, even during around ten years – the drop in strength is only ~1% (according to tests),
• They are extremely resistant to demagnetization induced by external disturbances,
• A magnet with a smooth nickel surface has better aesthetics,
• They feature high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Possibility of custom forming and modifying to precise conditions,
• Huge importance in innovative solutions – they are used in magnetic memories, motor assemblies, medical equipment, as well as complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

What to avoid - cons of neodymium magnets: application proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also improves its resistance to damage
• When exposed to high temperature, neodymium magnets suffer 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
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• We recommend casing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets can be dangerous, if swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small components of these magnets can be problematic in diagnostics medical after entering the body.
• With large orders the cost of neodymium magnets is a challenge,

Maximum holding power of the magnet – what contributes to it?

The specified lifting capacity concerns the maximum value, measured under optimal environment, specifically:

• on a block made of structural steel, effectively closing the magnetic flux
• with a thickness no less than 10 mm
• characterized by smoothness
• with direct contact (no coatings)
• for force acting at a right angle (in the magnet axis)
• at temperature approx. 20 degrees Celsius

Lifting capacity in real conditions – factors

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

• Clearance – the presence of foreign body (rust, tape, gap) interrupts the magnetic circuit, which reduces capacity rapidly (even by 50% at 0.5 mm).
• Load vector – maximum parameter is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the surface is standardly several times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Steel grade – ideal substrate is pure iron steel. Stainless steels may have worse magnetic properties.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was performed on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under attempts to slide the magnet the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet and the plate lowers the holding force.