BM 550x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They have stable power, and over more than 10 years their attraction force decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by external electromagnetic environments very well,
• Thanks to the glossy finish and silver coating, they have an visually attractive appearance,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• With the right combination of materials, they reach significant thermal stability, enabling operation at or above 230°C (depending on the form),
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in different geometries, which increases their functional possibilities,
• Important function in new technology industries – they are used in data storage devices, electric motors, medical equipment as well as high-tech tools,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They can break when subjected to a sudden impact. If the magnets are exposed to physical collisions, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and reinforces its overall strength,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (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,
• Magnets exposed to humidity can degrade. Therefore, for outdoor applications, we suggest waterproof types made of coated materials,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is restricted,
• Potential hazard related to magnet particles may arise, when consumed by mistake, which is crucial in the family environments. Additionally, minuscule fragments from these products can hinder health screening after being swallowed,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Optimal lifting capacity of a neodymium magnet – what affects it?

The given strength of the magnet represents the optimal strength, assessed in ideal conditions, specifically:

• with the use of low-carbon steel plate acting as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in practice – influencing factors

Practical lifting force is determined by elements, by priority:

• 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 testing was performed on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate decreases the lifting capacity.