UMGGW 22x6 [M4] GW / N38 - magnetic holder rubber internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They do not lose their power nearly 10 years – the loss of strength is only ~1% (according to tests),
• They show exceptional resistance to demagnetization from external field exposure,
• Because of the reflective layer of nickel, the component looks aesthetically refined,
• Magnetic induction on the surface of these magnets is very strong,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for accurate shaping or customization to individual needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which extends the scope of their use cases,
• Significant impact in modern technologies – they serve a purpose in HDDs, rotating machines, medical equipment or even technologically developed systems,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and reinforces its overall robustness,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a damp environment – during 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 restricted,
• Possible threat linked to microscopic shards may arise, when consumed by mistake, which is notable in the context of child safety. Furthermore, tiny components from these assemblies may hinder health screening when ingested,
• Due to the price of neodymium, their cost is relatively high,

Magnetic strength at its maximum – what it depends on?

The given pulling force of the magnet means the maximum force, assessed in the best circumstances, that is:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• in conditions of no clearance
• in a perpendicular direction of force
• at room temperature

Practical lifting capacity: influencing factors

In practice, the holding capacity of a magnet is conditioned by these factors, from crucial to less important:

• Air gap between the magnet and the plate, since 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 using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under shearing force the holding force is lower. In addition, even a small distance {between} the magnet and the plate decreases the lifting capacity.