BM 750x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their stability, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after 10 years, the decline in efficiency is only ~1% (based on calculations),
• They remain magnetized despite exposure to magnetic surroundings,
• Because of the lustrous layer of silver, the component looks aesthetically refined,
• They have extremely strong magnetic induction on the surface of the magnet,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• The ability for precise shaping and adjustment to individual needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Key role in new technology industries – they find application in HDDs, electric motors, medical equipment or even high-tech tools,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They can break when subjected to a strong impact. If the magnets are exposed to mechanical hits, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall robustness,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on height). 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 wet environment – during outdoor use, we recommend using moisture-resistant magnets, such as those made of non-metallic materials,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing holes directly in the magnet,
• Possible threat due to small fragments may arise, in case of ingestion, which is crucial in the context of child safety. Furthermore, miniature parts from these magnets may hinder health screening once in the system,
• Due to the price of neodymium, their cost is above average,

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

The given strength of the magnet means the optimal strength, calculated under optimal conditions, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Key elements affecting lifting force

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 testing was conducted on a smooth plate of suitable thickness, under a perpendicular pulling force, however under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet and the plate lowers the holding force.