SMZR 25x100 / N52 - magnetic separator with handle

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after ten years, the decline in efficiency is only ~1% (in laboratory conditions),
• They remain magnetized despite exposure to magnetic noise,
• Because of the brilliant layer of gold, the component looks high-end,
• They have extremely strong magnetic induction on the surface of the magnet,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• The ability for precise shaping as well as adaptation to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which amplifies their functionality across industries,
• Key role in modern technologies – they find application in HDDs, rotating machines, healthcare devices along with other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to mechanical hits, it is advisable to use in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage while also enhances its overall strength,
• 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 structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a wet environment, especially when used outside, we recommend using encapsulated magnets, such as those made of non-metallic materials,
• Limited ability to create threads in the magnet – the use of a external casing is recommended,
• Health risk due to small fragments may arise, when consumed by mistake, which is important in the health of young users. Additionally, small elements from these products can disrupt scanning if inside the body,
• In cases of large-volume purchasing, neodymium magnet cost may be a barrier,

Maximum lifting force for a neodymium magnet – what affects it?

The given strength of the magnet means the optimal strength, calculated in ideal conditions, that is:

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet is influenced by in practice key elements, according to their importance:

• Air gap between the magnet and the plate, because 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.

* Lifting capacity was determined by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the holding force.