NCM 15x13.5x5 / N38 - channel magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their stability, neodymium magnets are valued for these benefits:

• They virtually do not lose power, because even after 10 years, the decline in efficiency is only ~1% (based on calculations),
• They are extremely resistant to demagnetization caused by external field interference,
• In other words, due to the shiny gold coating, the magnet obtains an aesthetic appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• Thanks to their enhanced temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• The ability for accurate shaping and customization to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Important function in modern technologies – they serve a purpose in computer drives, electric motors, clinical machines and technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time increases its overall resistance,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to moisture can oxidize. Therefore, for outdoor applications, we advise waterproof types made of rubber,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing complex structures directly in the magnet,
• Safety concern from tiny pieces may arise, if ingested accidentally, which is notable in the health of young users. Moreover, tiny components from these magnets have the potential to complicate medical imaging if inside the body,
• In cases of tight budgets, neodymium magnet cost may be a barrier,

Maximum lifting capacity of the magnet – what it depends on?

The given lifting capacity of the magnet represents the maximum lifting force, assessed in the best circumstances, specifically:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• in conditions of no clearance
• under perpendicular detachment force
• under standard ambient temperature

What influences lifting capacity in practice

The lifting capacity of a magnet is determined by in practice key elements, ordered from most important to least 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 checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.