UMGZ 48x24x11.5 [M8] GZ / N38 - magnetic holder external thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

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

• They do not lose their strength approximately ten years – the loss of strength is only ~1% (based on measurements),
• They are extremely resistant to demagnetization caused by external magnetic fields,
• The use of a mirror-like nickel surface provides a eye-catching finish,
• Magnetic induction on the surface of these magnets is notably high,
• These magnets tolerate high temperatures, often exceeding 230°C, when properly designed (in relation to build),
• With the option for tailored forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving design adaptation,
• Key role in new technology industries – they are utilized in data storage devices, rotating machines, diagnostic apparatus as well as sophisticated instruments,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a strong 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 additionally strengthens its overall durability,
• High temperatures may significantly reduce the field efficiency of neodymium magnets. Typically, above 80°C, they experience permanent deterioration 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 rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining threads in neodymium magnets is not feasible,
• Possible threat due to small fragments may arise, in case of ingestion, which is notable in the family environments. It should also be noted that tiny components from these devices might complicate medical imaging if inside the body,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Breakaway strength of the magnet in ideal conditions – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, measured under optimal conditions, specifically:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a polished side
• with zero air gap
• under perpendicular detachment force
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

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 testing was carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.