MW 6x6 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their superior power, neodymium magnets have these key benefits:

• They virtually do not lose power, because even after 10 years, the performance loss is only ~1% (according to literature),
• They are very resistant to demagnetization caused by external magnetic fields,
• By applying a shiny layer of silver, the element gains a modern look,
• The outer field strength of the magnet shows elevated magnetic properties,
• With the right combination of compounds, they reach increased thermal stability, enabling operation at or above 230°C (depending on the design),
• Thanks to the flexibility in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in diverse shapes and sizes, which broadens their functional possibilities,
• Key role in new technology industries – they find application in HDDs, electromechanical systems, clinical machines as well as high-tech tools,
• Thanks to their power density, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of magnetic elements:

• They are fragile when subjected to a strong impact. If the magnets are exposed to shocks, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time increases its overall strength,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s form). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can degrade. Therefore, for outdoor applications, we advise waterproof types made of non-metallic composites,
• Limited ability to create precision features in the magnet – the use of a mechanical support is recommended,
• Potential hazard linked to microscopic shards may arise, in case of ingestion, which is crucial in the protection of children. It should also be noted that miniature parts from these devices might disrupt scanning when ingested,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Highest magnetic holding force – what it depends on?

The given strength of the magnet represents the optimal strength, determined under optimal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• in normal thermal conditions

Practical aspects of lifting capacity – factors

Practical lifting force is determined by 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.

* Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, however under shearing force the load capacity is reduced by as much as fivefold. In addition, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.