AM ucho [M8] - magnetic accessories

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• Their magnetic field is maintained, and after around 10 years, it drops only by ~1% (according to research),
• They are extremely resistant to demagnetization caused by external field interference,
• Because of the lustrous layer of nickel, the component looks visually appealing,
• Magnetic induction on the surface of these magnets is notably high,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• With the option for customized forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Important function in new technology industries – they are used in computer drives, electromechanical systems, medical equipment as well as other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in small dimensions, which makes them useful in small systems

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to physical collisions, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time enhances its overall robustness,
• 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 profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a damp environment. For outdoor use, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create complex details in the magnet – the use of a external casing is recommended,
• Health risk related to magnet particles may arise, if ingested accidentally, which is important in the health of young users. Moreover, tiny components from these assemblies have the potential to complicate medical imaging after being swallowed,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Maximum lifting force for a neodymium magnet – what it depends on?

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

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice the following factors, from primary to secondary:

• 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.