BM 950x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• Their strength remains stable, and after around ten years, it drops only by ~1% (according to research),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the brilliant layer of gold, the component looks visually appealing,
• The outer field strength of the magnet shows remarkable magnetic properties,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• With the option for customized forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Important function in cutting-edge sectors – they are utilized in hard drives, electric motors, diagnostic apparatus or even other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in tiny dimensions, which makes them ideal in compact constructions

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to external force, it is suggested to place them in a metal holder. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time reinforces its overall strength,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing holes directly in the magnet,
• Safety concern linked to microscopic shards may arise, in case of ingestion, which is significant in the family environments. Furthermore, small elements from these magnets have the potential to complicate medical imaging when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Magnetic strength at its maximum – what affects it?

The given holding capacity of the magnet means the highest holding force, determined in the best circumstances, that is:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a polished side
• with no separation
• under perpendicular detachment force
• at room temperature

Lifting capacity in real conditions – factors

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• Air gap between the magnet and the plate, because 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 testing was performed on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the holding force.