BM 750x180x70 [4x M8] - magnetic beam

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is maintained, and after around 10 years, it drops only by ~1% (theoretically),
• They are extremely resistant to demagnetization caused by external field interference,
• Because of the reflective layer of gold, the component looks high-end,
• They possess significant magnetic force measurable at the magnet’s surface,
• With the right combination of compounds, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• With the option for customized forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Significant impact in cutting-edge sectors – they serve a purpose in hard drives, electric drives, medical equipment as well as other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They can break when subjected to a powerful 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 cracks and additionally strengthens its overall durability,
• They lose strength at high temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the dimensions and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Magnets exposed to moisture can rust. Therefore, for outdoor applications, we advise waterproof types made of coated materials,
• Limited ability to create complex details in the magnet – the use of a magnetic holder is recommended,
• Potential hazard due to small fragments may arise, if ingested accidentally, which is notable in the health of young users. Additionally, tiny components from these products can complicate medical imaging if inside the body,
• In cases of mass production, neodymium magnet cost may be a barrier,

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

The given holding capacity of the magnet corresponds to the highest holding force, determined under optimal conditions, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• in a perpendicular direction of force
• at room temperature

Impact of factors on magnetic holding capacity in practice

Practical lifting force is determined by elements, by priority:

• 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 determined using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the load capacity.