HH 36x7.5 [M6] / N38 - through hole magnetic holder

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their immense pulling force, neodymium magnets offer the following advantages:

• They retain their full power for almost ten years – the loss is just ~1% (according to analyses),
• Their ability to resist magnetic interference from external fields is among the best,
• Thanks to the glossy finish and silver coating, they have an visually attractive appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• Thanks to the flexibility in shaping and the capability to adapt to unique requirements, neodymium magnets can be created in different geometries, which increases their functional possibilities,
• Key role in cutting-edge sectors – they are utilized in HDDs, electric motors, clinical machines along with high-tech tools,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They can break when subjected to a sudden impact. If the magnets are exposed to physical collisions, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from breakage and enhances its overall durability,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible power drop (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,
• Due to corrosion risk in humid conditions, it is wise to use sealed magnets made of rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is risky,
• Safety concern related to magnet particles may arise, when consumed by mistake, which is significant in the family environments. Furthermore, tiny components from these products may complicate medical imaging if inside the body,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting force for a neodymium magnet – what contributes to it?

The given pulling force of the magnet represents the maximum force, calculated in ideal 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 smooth surface
• with zero air gap
• under perpendicular detachment force
• under standard ambient temperature

Determinants of lifting force in real conditions

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• 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.

* Lifting capacity was determined by applying a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under shearing force the load capacity is reduced by as much as 75%. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.