UMGB 97x40 [M8+M10] GW F300 +Lina GOBLIN / N38 - goblin magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They virtually do not lose strength, because even after 10 years, the performance loss is only ~1% (based on calculations),
• They are very resistant to demagnetization caused by external magnetic sources,
• In other words, due to the metallic silver coating, the magnet obtains an stylish appearance,
• They possess significant magnetic force measurable at the magnet’s surface,
• 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 tailored forming and precise design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Important function in new technology industries – they find application in HDDs, electric drives, clinical machines or even sophisticated instruments,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of rare earth magnets:

• They can break when subjected to a strong impact. If the magnets are exposed to external force, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time increases its overall robustness,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent decline 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,
• They rust in a humid environment, especially when used outside, we recommend using waterproof magnets, such as those made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the difficulty in manufacturing threads directly in the magnet,
• Potential hazard due to small fragments may arise, in case of ingestion, which is crucial in the health of young users. It should also be noted that tiny components from these devices may complicate medical imaging once in the system,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which may limit large-scale applications

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

The given pulling force of the magnet corresponds to the maximum force, assessed in ideal conditions, specifically:

• with the use of low-carbon steel plate acting as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

Impact of factors on magnetic holding capacity in practice

Practical lifting force is dependent on factors, by priority:

• 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 performed on plates with a smooth surface of suitable thickness, under perpendicular forces, whereas under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a slight gap {between} the magnet and the plate reduces the holding force.