BM 700x180x75 [8xM10] - magnetic beam

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They do not lose their power nearly ten years – the reduction of lifting capacity is only ~1% (according to tests),
• Their ability to resist magnetic interference from external fields is impressive,
• By applying a bright layer of gold, the element gains a modern look,
• Magnetic induction on the surface of these magnets is very strong,
• With the right combination of magnetic alloys, they reach significant thermal stability, enabling operation at or above 230°C (depending on the structure),
• The ability for accurate shaping as well as customization to custom needs – neodymium magnets can be manufactured in many forms and dimensions, which extends the scope of their use cases,
• Key role in modern technologies – they are utilized in data storage devices, rotating machines, medical equipment or even sophisticated instruments,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a sudden impact. If the magnets are exposed to external force, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage while also enhances its overall durability,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on shape). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• They rust in a humid environment – during outdoor use, 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 magnetic holder is recommended,
• Potential hazard related to magnet particles may arise, especially if swallowed, which is significant in the context of child safety. Furthermore, minuscule fragments from these assemblies can hinder health screening once in the system,
• In cases of large-volume purchasing, neodymium magnet cost may be a barrier,

Maximum lifting force for a neodymium magnet – what it depends on?

The given holding capacity of the magnet represents the highest holding force, calculated in ideal conditions, that is:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with zero air gap
• with vertical force applied
• at room temperature

What influences lifting capacity in practice

In practice, the holding capacity of a magnet is conditioned by these factors, from crucial to less important:

• Air gap between the magnet and the plate, since 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 perpendicular forces, in contrast under shearing force the holding force is lower. Additionally, even a small distance {between} the magnet and the plate lowers the lifting capacity.