UMGGW 34x8 [M4] GW / N38 - magnetic holder rubber internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetic energy, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They are highly resistant to demagnetization caused by external magnetic fields,
• Because of the lustrous layer of nickel, the component looks aesthetically refined,
• Magnetic induction on the surface of these magnets is very strong,
• With the right combination of magnetic alloys, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the structure),
• The ability for precise shaping or adjustment to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which extends the scope of their use cases,
• Wide application in new technology industries – they find application in hard drives, electric drives, medical equipment along with high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in small dimensions, which makes them useful in miniature devices

Disadvantages of neodymium magnets:

• They are fragile when subjected to a powerful 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 breakage , and at the same time enhances its overall robustness,
• They lose field intensity at high temperatures. Most neodymium magnets experience permanent loss in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• They rust in a moist environment. For outdoor use, we recommend using moisture-resistant magnets, such as those made of polymer,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is difficult,
• Possible threat due to small fragments may arise, when consumed by mistake, which is significant in the protection of children. It should also be noted that miniature parts from these devices may hinder health screening once in the system,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Magnetic strength at its maximum – what it depends on?

The given holding capacity of the magnet corresponds to the highest holding force, measured in the best circumstances, specifically:

• with mild steel, used as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a polished side
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet depends on in practice the following factors, 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.

* Lifting capacity was measured using a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a minimal clearance {between} the magnet and the plate reduces the holding force.