BM 950x180x70 [4x M8] - magnetic beam

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They retain their full power for almost ten years – the drop is just ~1% (according to analyses),
• They are highly resistant to demagnetization caused by external magnetic sources,
• By applying a reflective layer of gold, the element gains a clean look,
• Magnetic induction on the surface of these magnets is very strong,
• 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 shape),
• With the option for tailored forming and personalized design, these magnets can be produced in multiple shapes and sizes, greatly improving design adaptation,
• Key role in new technology industries – they are used in hard drives, rotating machines, diagnostic apparatus or even technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They may fracture when subjected to a sudden impact. If the magnets are exposed to mechanical hits, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture and additionally enhances its overall resistance,
• They lose power at increased temperatures. Most neodymium magnets experience permanent degradation 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 damp air can rust. Therefore, for outdoor applications, we advise waterproof types made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing threads directly in the magnet,
• Health risk linked to microscopic shards may arise, in case of ingestion, which is notable in the family environments. Furthermore, miniature parts from these products might disrupt scanning after being swallowed,
• Due to a complex production process, their cost is above average,

Breakaway strength of the magnet in ideal conditions – what affects it?

The given strength of the magnet represents the optimal strength, calculated under optimal conditions, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Determinants of practical lifting force of a magnet

Practical lifting force is dependent on factors, 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) 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 by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a slight gap {between} the magnet and the plate reduces the load capacity.