UMGZ 42x20x9 [M8] GZ / N38 - magnetic holder external thread

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• Their magnetic field is durable, and after approximately 10 years, it drops only by ~1% (according to research),
• They are extremely resistant to demagnetization caused by external magnetic sources,
• Because of the lustrous layer of gold, the component looks aesthetically refined,
• They possess significant magnetic force measurable at the magnet’s surface,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• With the option for tailored forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Wide application in new technology industries – they serve a purpose in data storage devices, electromechanical systems, diagnostic apparatus or even sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in tiny dimensions, which allows for use in small systems

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to external force, they should be placed in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time strengthens its overall resistance,
• They lose magnetic force at elevated temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is recommended to use sealed magnets made of plastic for outdoor use,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is restricted,
• Possible threat linked to microscopic shards may arise, especially if swallowed, which is crucial in the protection of children. Additionally, miniature parts from these magnets can complicate medical imaging when ingested,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Maximum holding power of the magnet – what contributes to it?

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

• using a steel plate with low carbon content, serving 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
• under standard ambient temperature

Magnet lifting force in use – key factors

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• Air gap between the magnet and the plate, since 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 checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the load capacity is reduced by as much as 75%. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.