SM 32x200 [2xM8] / N52 - magnetic separator

Advantages and disadvantages of neodymium magnets NdFeB.

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

• Their power remains stable, and after around 10 years, it drops only by ~1% (according to research),
• They show exceptional resistance to demagnetization from external magnetic fields,
• By applying a shiny layer of gold, the element gains a sleek look,
• They have very high magnetic induction on the surface of the magnet,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• The ability for accurate shaping and adjustment to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Significant impact in modern technologies – they serve a purpose in data storage devices, rotating machines, healthcare devices as well as high-tech tools,
• Thanks to their power density, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of rare earth magnets:

• They are fragile when subjected to a strong impact. If the magnets are exposed to mechanical hits, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall durability,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible power drop (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing holes directly in the magnet,
• Potential hazard due to small fragments may arise, when consumed by mistake, which is important in the family environments. It should also be noted that small elements from these products may interfere with diagnostics if inside the body,
• Due to expensive raw materials, their cost is above average,

Maximum lifting capacity of the magnet – what affects it?

The given strength of the magnet represents the optimal strength, calculated in the best circumstances, specifically:

• with mild steel, used as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• with zero air gap
• under perpendicular detachment force
• at room temperature

What influences lifting capacity in practice

The lifting capacity of a magnet depends on in practice key elements, ordered from most important to least significant:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate reduces the holding force.