UMGW 75x33x18 [M10] GW / N38 - magnetic holder internal thread

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after 10 years, the performance loss is only ~1% (based on calculations),
• They show exceptional resistance to demagnetization from external magnetic fields,
• The use of a decorative gold surface provides a eye-catching finish,
• The outer field strength of the magnet shows elevated magnetic properties,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for accurate shaping and adaptation to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which amplifies their functionality across industries,
• Important function in cutting-edge sectors – they are used in HDDs, electric motors, healthcare devices along with other advanced devices,
• Thanks to their power density, small magnets offer high magnetic performance, in miniature format,

Disadvantages of neodymium magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to shocks, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and additionally increases its overall durability,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent reduction 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,
• Magnets exposed to moisture can corrode. Therefore, for outdoor applications, we suggest waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining internal cuts in neodymium magnets is not feasible,
• Health risk due to small fragments may arise, if ingested accidentally, which is crucial in the family environments. Additionally, miniature parts from these devices can hinder health screening if inside the body,
• In cases of mass production, neodymium magnet cost is a challenge,

Detachment force of the magnet in optimal conditions – what contributes to it?

The given holding capacity of the magnet represents the highest holding force, assessed in ideal conditions, namely:

• 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 zero air gap
• under perpendicular detachment force
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet depends on in practice key elements, according to their importance:

• 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 testing was conducted on plates with a smooth surface of suitable thickness, under perpendicular forces, however under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet and the plate decreases the load capacity.