WM 34.5x24.3x17 / N38 - magnetic hanger

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They have unchanged lifting capacity, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• Their ability to resist magnetic interference from external fields is among the best,
• In other words, due to the glossy gold coating, the magnet obtains an aesthetic appearance,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in various configurations, which broadens their usage potential,
• Wide application in advanced technical fields – they serve a purpose in hard drives, rotating machines, diagnostic apparatus and other advanced devices,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in small dimensions, which makes them useful in miniature devices

Disadvantages of neodymium magnets:

• They may fracture when subjected to a sudden impact. If the magnets are exposed to external force, it is suggested to place them in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture and additionally increases its overall durability,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (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,
• They rust in a moist environment – during outdoor use, we recommend using sealed magnets, such as those made of polymer,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is restricted,
• Health risk due to small fragments may arise, if ingested accidentally, which is significant in the family environments. Moreover, small elements from these products might interfere with diagnostics once in the system,
• In cases of mass production, neodymium magnet cost is a challenge,

Breakaway strength of the magnet in ideal conditions – what it depends on?

The given lifting capacity of the magnet corresponds to the maximum lifting force, measured in the best circumstances, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

What influences lifting capacity in practice

Practical lifting force is dependent on elements, 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 a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate decreases the load capacity.