UMS 60x18x8.5x15 / N38 - conical magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their remarkable field intensity, neodymium magnets offer the following advantages:

• They do not lose their power around ten years – the decrease of strength is only ~1% (theoretically),
• They remain magnetized despite exposure to magnetic noise,
• Thanks to the shiny finish and gold coating, they have an visually attractive appearance,
• Magnetic induction on the surface of these magnets is very strong,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• With the option for customized forming and targeted design, these magnets can be produced in multiple shapes and sizes, greatly improving application potential,
• Wide application in modern technologies – they are utilized in HDDs, electromechanical systems, healthcare devices or even sophisticated instruments,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They can break when subjected to a strong impact. If the magnets are exposed to shocks, it is suggested to place them in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from cracks and strengthens its overall robustness,
• Magnets lose power when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (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,
• They rust in a moist environment – during outdoor use, we recommend using moisture-resistant magnets, such as those made of plastic,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is not feasible,
• Possible threat linked to microscopic shards may arise, if ingested accidentally, which is notable in the context of child safety. Furthermore, minuscule fragments from these products might hinder health screening when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

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

The given strength of the magnet represents the optimal strength, calculated in the best circumstances, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• under standard ambient temperature

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is conditioned by these factors, arranged from the most important to the least relevant:

• 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 carried out on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under parallel forces the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.