BM 950x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their remarkable strength, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• They are extremely resistant to demagnetization caused by external field interference,
• Because of the lustrous layer of silver, the component looks high-end,
• They exhibit superior levels of magnetic induction near the outer area of the magnet,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• The ability for custom shaping as well as adjustment to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Key role in modern technologies – they are utilized in hard drives, electric motors, diagnostic apparatus and technologically developed systems,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to shocks, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and enhances its overall durability,
• They lose power at extreme temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a damp environment, especially when used outside, we recommend using encapsulated magnets, such as those made of polymer,
• Limited ability to create threads in the magnet – the use of a magnetic holder is recommended,
• Safety concern due to small fragments may arise, if ingested accidentally, which is crucial in the context of child safety. It should also be noted that tiny components from these magnets have the potential to complicate medical imaging when ingested,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Detachment force of the magnet in optimal conditions – what contributes to it?

The given pulling force of the magnet represents the maximum force, measured in the best circumstances, specifically:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with no separation
• with vertical force applied
• in normal thermal conditions

Magnet lifting force in use – key factors

Practical lifting force is dependent on elements, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, since even a very small distance (e.g. 0.5 mm) causes 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 assessed using a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under shearing force the holding force is lower. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.