UMP 75x25 [M10x3] GW F200 PLATINIUM / N52 - search holder

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 strength, because even after 10 years, the performance loss is only ~1% (according to literature),
• Their ability to resist magnetic interference from external fields is among the best,
• Thanks to the shiny finish and nickel coating, they have an visually attractive appearance,
• The outer field strength of the magnet shows remarkable magnetic properties,
• With the right combination of compounds, they reach increased thermal stability, enabling operation at or above 230°C (depending on the structure),
• 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 modern technologies – they are used in data storage devices, rotating machines, clinical machines along with technologically developed systems,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, with minimal size,

Disadvantages of rare earth magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to external force, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture and additionally increases its overall robustness,
• They lose strength at elevated 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 rubber for outdoor use,
• The use of a protective casing or external holder is recommended, since machining fine details in neodymium magnets is restricted,
• Safety concern from tiny pieces may arise, if ingested accidentally, which is important in the protection of children. Additionally, small elements from these devices may hinder health screening once in the system,
• Due to a complex production process, their cost is above average,

Maximum lifting capacity of the magnet – what it depends on?

The given pulling force of the magnet corresponds to the maximum force, determined under optimal conditions, namely:

• with mild steel, serving as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a smooth surface
• with no separation
• with vertical force applied
• at room temperature

Determinants of practical lifting force of a magnet

Practical lifting force is determined by elements, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because 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 parallel forces the load capacity is reduced by as much as 75%. Additionally, even a small distance {between} the magnet and the plate lowers the load capacity.