UMGW 16x13x5 [M4] GW / N38 - magnetic holder internal thread

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their exceptional strength, neodymium magnets offer the following advantages:

• They have constant strength, 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,
• Thanks to the polished finish and silver coating, they have an elegant appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• With the right combination of materials, they reach increased thermal stability, enabling operation at or above 230°C (depending on the design),
• Thanks to the possibility in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in various configurations, which expands their usage potential,
• Wide application in cutting-edge sectors – they are utilized in HDDs, electric motors, medical equipment as well as high-tech tools,
• Relatively small size with high magnetic force – neodymium magnets offer strong power in compact dimensions, which makes them ideal in small systems

Disadvantages of NdFeB magnets:

• They are prone to breaking when subjected to a strong impact. If the magnets are exposed to physical collisions, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from breakage while also strengthens its overall strength,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on size). 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 advisable to use sealed magnets made of synthetic coating for outdoor use,
• Limited ability to create complex details in the magnet – the use of a magnetic holder is recommended,
• Health risk linked to microscopic shards may arise, especially if swallowed, which is notable in the health of young users. Furthermore, minuscule fragments from these devices might complicate medical imaging once in the system,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Highest magnetic holding force – what it depends on?

The given pulling force of the magnet corresponds to the maximum force, measured in ideal conditions, specifically:

• with the use of low-carbon steel plate acting as a magnetic yoke
• of a thickness of at least 10 mm
• with a refined outer layer
• with no separation
• under perpendicular detachment force
• in normal thermal conditions

Key elements affecting lifting force

Practical lifting force is dependent on elements, listed from the most critical to the less significant:

• 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 measured by applying a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet’s surface and the plate decreases the load capacity.