SM 18x200 [2xM5] / N42 - magnetic separator

Strengths as well as weaknesses of NdFeB magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (in laboratory conditions),
• Magnets effectively resist against loss of magnetization caused by foreign field sources,
• The use of an aesthetic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Magnetic induction on the working layer of the magnet is 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...
• Thanks to flexibility in forming and the capacity to customize to unusual requirements,
• Fundamental importance in innovative solutions – they are utilized in HDD drives, electromotive mechanisms, diagnostic systems, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in compact constructions

Disadvantages of NdFeB magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. 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 strength decreases (depending on the size and 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 suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We recommend casing - magnetic mount, due to difficulties in realizing threads inside the magnet and complicated forms.
• Potential hazard resulting from small fragments of magnets can be dangerous, in case of ingestion, which gains importance in the context of child safety. Additionally, small elements of these magnets can complicate diagnosis medical after entering the body.
• With mass production the cost of neodymium magnets can be a barrier,

Breakaway strength of the magnet in ideal conditions – what it depends on?

Breakaway force was defined for optimal configuration, including:

• using a sheet made of mild steel, acting as a ideal flux conductor
• whose thickness is min. 10 mm
• with a surface free of scratches
• with zero gap (no coatings)
• during detachment in a direction perpendicular to the plane
• at ambient temperature room level

Lifting capacity in real conditions – factors

Effective lifting capacity is influenced by working environment parameters, mainly (from priority):

• Distance (between the magnet and the plate), because even a microscopic distance (e.g. 0.5 mm) results in a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of converting into lifting capacity.
• Plate material – low-carbon steel gives the best results. Higher carbon content decrease magnetic properties and holding force.
• Surface finish – ideal contact is obtained only on polished steel. Rough texture reduce the real contact area, weakening the magnet.
• Temperature – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under parallel forces the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.