HH 20x7.2 [M4] / N38 - through hole magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their remarkable field intensity, neodymium magnets offer the following advantages:

• They retain their full power for around ten years – the loss is just ~1% (according to analyses),
• They show exceptional resistance to demagnetization from external field exposure,
• In other words, due to the metallic silver coating, the magnet obtains an professional appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• Thanks to the freedom in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in various configurations, which increases their usage potential,
• Important function in new technology industries – they are utilized in hard drives, electric motors, medical equipment as well as technologically developed systems,
• Compactness – despite their small size, they generate strong force, 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 external force, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from damage while also enhances its overall durability,
• Magnets lose field strength when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to humidity can corrode. Therefore, for outdoor applications, it's best to use waterproof types made of plastic,
• Limited ability to create precision features in the magnet – the use of a magnetic holder is recommended,
• Potential hazard due to small fragments may arise, if ingested accidentally, which is notable in the protection of children. Moreover, small elements from these assemblies can complicate medical imaging if inside the body,
• Due to the price of neodymium, their cost is above average,

Detachment force of the magnet in optimal conditions – what it depends on?

The given strength of the magnet represents the optimal strength, calculated in the best circumstances, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• with a thickness of minimum 10 mm
• with a smooth surface
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Practical aspects of lifting capacity – factors

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• Air gap between the magnet and the plate, as 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 plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under parallel forces the load capacity is reduced by as much as 75%. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the holding force.