SM 32x425 [2xM8] / N52 - magnetic separator

Pros and cons of NdFeB magnets.

Apart from their notable magnetism, neodymium magnets have these key benefits:

• They retain attractive force for almost 10 years – the drop is just ~1% (in theory),
• They are noted for resistance to demagnetization induced by external field influence,
• In other words, due to the aesthetic surface of nickel, the element is aesthetically pleasing,
• Magnetic induction on the top side of the magnet turns out to be very high,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Considering the potential of precise forming and customization to unique requirements, neodymium magnets can be produced in a wide range of forms and dimensions, which amplifies use scope,
• Significant place in modern industrial fields – they are used in mass storage devices, electric motors, diagnostic systems, as well as technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• Limited possibility of making nuts in the magnet and complicated shapes - preferred is casing - mounting mechanism.
• Possible danger resulting from small fragments of magnets pose a threat, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Furthermore, tiny parts of these products are able to be problematic in diagnostics medical in case of swallowing.
• Due to expensive raw materials, their price is higher than average,

Maximum lifting force for a neodymium magnet – what contributes to it?

The specified lifting capacity represents the limit force, obtained under ideal test conditions, meaning:

• on a base made of mild steel, optimally conducting the magnetic flux
• whose transverse dimension is min. 10 mm
• with an polished touching surface
• under conditions of no distance (surface-to-surface)
• for force acting at a right angle (in the magnet axis)
• in temp. approx. 20°C

Determinants of practical lifting force of a magnet

In practice, the actual holding force results from a number of factors, ranked from the most important:

• Distance (betwixt the magnet and the plate), because even a microscopic distance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Force direction – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux passes through the material instead of converting into lifting capacity.
• Plate material – low-carbon steel gives the best results. Alloy steels lower magnetic permeability and holding force.
• Surface condition – smooth surfaces guarantee perfect abutment, which increases force. Uneven metal weaken the grip.
• Heat – NdFeB sinters have a negative temperature coefficient. At higher temperatures they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.