UMGGZ 43x6 [M6] GZ / N38 - rubber magnetic holder external thread

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They have constant strength, and over more than ten years their attraction force decreases symbolically – ~1% (according to theory),
• They are very resistant to demagnetization caused by external magnetic sources,
• Because of the brilliant layer of nickel, the component looks visually appealing,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to build),
• Thanks to the possibility in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in different geometries, which expands their usage potential,
• Wide application in advanced technical fields – they are utilized in hard drives, electromechanical systems, diagnostic apparatus and high-tech tools,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of NdFeB magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to physical collisions, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and additionally strengthens its overall durability,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible power drop (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Due to corrosion risk in humid conditions, it is wise to use sealed magnets made of plastic for outdoor use,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is risky,
• Possible threat due to small fragments may arise, in case of ingestion, which is crucial in the family environments. Additionally, small elements from these assemblies can hinder health screening when ingested,
• In cases of mass production, neodymium magnet cost may not be economically viable,

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

The given lifting capacity of the magnet means the maximum lifting force, determined under optimal conditions, that is:

• with mild steel, serving as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a smooth surface
• with zero air gap
• in a perpendicular direction of force
• under standard ambient temperature

Determinants of practical lifting force of a magnet

Practical lifting force is dependent on elements, by priority:

• 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.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet and the plate lowers the lifting capacity.