UMGW 75x33x18 [M10] GW / N38 - magnetic holder internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They do not lose their power nearly ten years – the loss of strength is only ~1% (theoretically),
• They are very resistant to demagnetization caused by external field interference,
• Because of the reflective layer of silver, the component looks visually appealing,
• The outer field strength of the magnet shows elevated magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for accurate shaping and adjustment to custom needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Wide application in modern technologies – they are used in data storage devices, electric motors, diagnostic apparatus or even other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture while also increases its overall robustness,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on shape). 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,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is not feasible,
• Potential hazard from tiny pieces may arise, when consumed by mistake, which is crucial in the family environments. Furthermore, small elements from these assemblies can disrupt scanning if inside the body,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which may limit large-scale applications

Optimal lifting capacity of a neodymium magnet – what it depends on?

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

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• in conditions of no clearance
• in a perpendicular direction of force
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

Practical lifting force is determined by factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because 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.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.