KM HF - 11,3 kg - magnetic bracket

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They virtually do not lose strength, because even after 10 years, the performance loss is only ~1% (in laboratory conditions),
• They protect against demagnetization induced by ambient magnetic fields remarkably well,
• Thanks to the shiny finish and nickel coating, they have an visually attractive appearance,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• With the option for tailored forming and precise design, these magnets can be produced in various shapes and sizes, greatly improving application potential,
• Key role in modern technologies – they are used in data storage devices, electromechanical systems, medical equipment along with technologically developed systems,
• Thanks to their power density, small magnets offer high magnetic performance, with minimal size,

Disadvantages of neodymium magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time strengthens its overall durability,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the geometry and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a humid environment, especially when used outside, we recommend using encapsulated magnets, such as those made of rubber,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Health risk related to magnet particles may arise, in case of ingestion, which is important in the family environments. Moreover, small elements from these products might interfere with diagnostics once in the system,
• Due to a complex production process, their cost is considerably higher,

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

The given pulling force of the magnet represents the maximum force, measured in a perfect environment, that is:

• with the use of low-carbon steel plate serving as a magnetic yoke
• of a thickness of at least 10 mm
• with a smooth surface
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice the following factors, ordered from most important to least significant:

• 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 using a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet and the plate reduces the load capacity.