UMGW 25x17x8 [M5] GW / N38 - magnetic holder internal thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from their notable power, neodymium magnets have these key benefits:

• Their strength remains stable, and after around ten years, it drops only by ~1% (according to research),
• They show strong resistance to demagnetization from external field exposure,
• Thanks to the polished finish and nickel coating, they have an aesthetic appearance,
• Magnetic induction on the surface of these magnets is impressively powerful,
• These magnets tolerate elevated temperatures, often exceeding 230°C, when properly designed (in relation to form),
• Thanks to the possibility in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in various configurations, which expands their usage potential,
• Important function in new technology industries – they serve a purpose in computer drives, electric motors, diagnostic apparatus or even other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a sudden impact. If the magnets are exposed to shocks, 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 additionally strengthens its overall strength,
• They lose strength at increased temperatures. Most neodymium magnets experience permanent degradation in strength when heated above 80°C (depending on the shape and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
• Due to corrosion risk in humid conditions, it is advisable to use sealed magnets made of plastic for outdoor use,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is risky,
• Safety concern from tiny pieces may arise, especially if swallowed, which is significant in the protection of children. Furthermore, tiny components from these devices have the potential to interfere with diagnostics if inside the body,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which may limit large-scale applications

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

The given pulling force of the magnet means the maximum force, calculated under optimal conditions, namely:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a smooth surface
• with no separation
• in a perpendicular direction of force
• in normal thermal conditions

Lifting capacity in real conditions – factors

Practical lifting force is dependent on factors, by priority:

• 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 a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate reduces the load capacity.