UMGZ 48x24x11.5 [M8] GZ / N38 - magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is maintained, and after around ten years, it drops only by ~1% (according to research),
• They are very resistant to demagnetization caused by external magnetic sources,
• By applying a reflective layer of nickel, the element gains a clean look,
• Magnetic induction on the surface of these magnets is very strong,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• Thanks to the freedom in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which expands their functional possibilities,
• Wide application in advanced technical fields – they are used in HDDs, electric motors, medical equipment along with high-tech tools,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are prone to breaking when subjected to a powerful 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 additionally strengthens its overall robustness,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on height). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Magnets exposed to damp air can degrade. Therefore, for outdoor applications, we recommend waterproof types made of plastic,
• Limited ability to create threads in the magnet – the use of a external casing is recommended,
• Health risk due to small fragments may arise, when consumed by mistake, which is significant in the protection of children. It should also be noted that miniature parts from these devices might complicate medical imaging once in the system,
• In cases of mass production, neodymium magnet cost may not be economically viable,

Detachment force of the magnet in optimal conditions – what it depends on?

The given strength of the magnet corresponds to the optimal strength, assessed in the best circumstances, specifically:

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

Practical aspects of lifting capacity – factors

In practice, the holding capacity of a magnet is conditioned by the following aspects, in descending order of importance:

• 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.

* Lifting capacity was determined by applying a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.