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

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They retain their full power for around ten years – the drop is just ~1% (in theory),
• They are highly resistant to demagnetization caused by external magnetic sources,
• The use of a mirror-like silver surface provides a smooth finish,
• They possess strong magnetic force measurable at the magnet’s surface,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• With the option for customized forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Wide application in modern technologies – they are utilized in computer drives, electromechanical systems, healthcare devices as well as sophisticated instruments,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, with minimal size,

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a heavy impact. If the magnets are exposed to shocks, we recommend in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and additionally strengthens its overall durability,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on size). 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,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is risky,
• Safety concern from tiny pieces may arise, especially if swallowed, which is important in the family environments. Moreover, minuscule fragments from these products can hinder health screening once in the system,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Best holding force of the magnet in ideal parameters – what contributes to it?

The given lifting capacity of the magnet corresponds to the maximum lifting force, assessed in ideal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a smooth surface
• with no separation
• with vertical force applied
• under standard ambient temperature

Practical aspects of lifting capacity – factors

Practical lifting force is determined by elements, by priority:

• 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.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.