UMGW 36x18x8 [M8] GW / N38 - magnetic holder internal thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They have unchanged lifting capacity, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They are extremely resistant to demagnetization caused by external magnetic fields,
• By applying a bright layer of silver, the element gains a modern look,
• The outer field strength of the magnet shows advanced magnetic properties,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• With the option for fine forming and targeted design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
• Significant impact in cutting-edge sectors – they serve a purpose in HDDs, rotating machines, healthcare devices as well as technologically developed systems,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to mechanical hits, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture and reinforces its overall strength,
• High temperatures may significantly reduce the strength of neodymium magnets. Typically, above 80°C, they experience permanent loss 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,
• They rust in a wet environment, especially when used outside, we recommend using waterproof magnets, such as those made of polymer,
• Using a cover – such as a magnetic holder – is advised due to the restrictions in manufacturing complex structures directly in the magnet,
• Potential hazard linked to microscopic shards may arise, especially if swallowed, which is notable in the context of child safety. Additionally, tiny components from these devices might disrupt scanning after being swallowed,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Maximum lifting force for a neodymium magnet – what contributes to it?

The given lifting capacity of the magnet represents the maximum lifting force, assessed under optimal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• at room temperature

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is affected by the following aspects, arranged from the most important to the least relevant:

• 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 measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet and the plate lowers the lifting capacity.