SM 32x250 [2xM8] / N52 - magnetic separator

Pros and cons of rare earth magnets.

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

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• Magnets very well resist against loss of magnetization caused by ambient magnetic noise,
• By applying a decorative layer of nickel, the element has an proper look,
• They are known for 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 work (depending on the shape) even at a temperature of 230°C or more...
• Thanks to freedom in designing and the capacity to modify to individual projects,
• Versatile presence in electronics industry – they find application in data components, electric drive systems, medical equipment, and industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Cons of neodymium magnets and ways of using them

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• Neodymium magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is casing - magnet mounting.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these devices can disrupt the diagnostic process medical when they are in the body.
• Due to neodymium price, their price exceeds standard values,

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

The declared magnet strength refers to the maximum value, measured under optimal environment, meaning:

• with the contact of a yoke made of special test steel, guaranteeing maximum field concentration
• with a cross-section no less than 10 mm
• characterized by smoothness
• with zero gap (no coatings)
• under perpendicular force direction (90-degree angle)
• at temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

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

• Distance – existence of any layer (rust, tape, gap) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Force direction – note that the magnet holds strongest perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Steel thickness – insufficiently thick steel does not close the flux, causing part of the power to be wasted to the other side.
• Steel type – low-carbon steel gives the best results. Alloy steels decrease magnetic properties and lifting capacity.
• Surface structure – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Operating temperature – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.