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

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They have stable power, and over around 10 years their performance decreases symbolically – ~1% (in testing),
• They protect against demagnetization induced by external magnetic influence effectively,
• In other words, due to the shiny gold coating, the magnet obtains an aesthetic appearance,
• Magnetic induction on the surface of these magnets is very strong,
• These magnets tolerate high 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 multiple shapes and sizes, greatly improving design adaptation,
• Significant impact in cutting-edge sectors – they serve a purpose in data storage devices, rotating machines, medical equipment or even high-tech tools,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to shocks, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time enhances its overall resistance,
• High temperatures may significantly reduce the holding force of neodymium magnets. Typically, above 80°C, they experience permanent deterioration in performance (depending on form). 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,
• They rust in a damp environment. For outdoor use, we recommend using waterproof magnets, such as those made of rubber,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is not feasible,
• Potential hazard due to small fragments may arise, in case of ingestion, which is notable in the protection of children. Furthermore, miniature parts from these devices can hinder health screening if inside the body,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Highest magnetic holding force – what contributes to it?

The given pulling force of the magnet means the maximum force, measured in the best circumstances, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a polished side
• with no separation
• with vertical force applied
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet is influenced by in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, because 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 tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet and the plate lowers the holding force.