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

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• Their strength is durable, and after approximately 10 years, it drops only by ~1% (theoretically),
• Their ability to resist magnetic interference from external fields is impressive,
• Thanks to the shiny finish and nickel coating, they have an elegant appearance,
• They possess strong magnetic force measurable at the magnet’s surface,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to profile),
• Thanks to the possibility in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in different geometries, which broadens their application range,
• Significant impact in modern technologies – they are utilized in computer drives, rotating machines, healthcare devices along with sophisticated instruments,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They can break when subjected to a heavy impact. If the magnets are exposed to mechanical hits, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage and additionally increases its overall strength,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent loss in performance (depending on height). 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 wise to use sealed magnets made of synthetic coating for outdoor use,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is restricted,
• Potential hazard from tiny pieces may arise, especially if swallowed, which is crucial in the health of young users. It should also be noted that tiny components from these devices might disrupt scanning after being swallowed,
• Due to the price of neodymium, their cost is above average,

Maximum holding power of the magnet – what it depends on?

The given strength of the magnet means the optimal strength, assessed in ideal conditions, specifically:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• under perpendicular detachment force
• in normal thermal conditions

Determinants of practical lifting force of a magnet

The lifting capacity of a magnet is influenced by in practice the following factors, from primary to secondary:

• Air gap between the magnet and the plate, as 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 assessed using a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under attempts to slide the magnet the holding force is lower. Moreover, even a small distance {between} the magnet and the plate reduces the lifting capacity.