BM 850x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their magnetic properties for almost ten years – the drop is just ~1% (according to analyses),
• They remain magnetized despite exposure to magnetic surroundings,
• Thanks to the glossy finish and silver coating, they have an elegant appearance,
• They have very high magnetic induction on the surface of the magnet,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• The ability for accurate shaping and adaptation to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which amplifies their functionality across industries,
• Significant impact in new technology industries – they are utilized in HDDs, electromechanical systems, diagnostic apparatus as well as high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in small systems

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to shocks, it is suggested to place them in a metal holder. The steel housing, in the form of a holder, protects the magnet from breakage and increases its overall resistance,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we advise waterproof types made of non-metallic composites,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing fine shapes directly in the magnet,
• Possible threat due to small fragments may arise, especially if swallowed, which is important in the health of young users. It should also be noted that small elements from these products may complicate medical imaging after being swallowed,
• In cases of mass production, neodymium magnet cost may not be economically viable,

Maximum lifting capacity of the magnet – what affects it?

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

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

Determinants of practical lifting force of a magnet

Practical lifting force is determined by elements, by priority:

• Air gap between the magnet and the plate, as 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 measured using a steel plate with a smooth surface of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate reduces the load capacity.