UMP 97x40 [M8+M10] GW F300 kg / N38 - search holder

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after ten years, the performance loss is only ~1% (based on calculations),
• Their ability to resist magnetic interference from external fields is impressive,
• Because of the brilliant layer of gold, the component looks visually appealing,
• The outer field strength of the magnet shows elevated magnetic properties,
• Neodymium magnets are known for very high magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• With the option for customized forming and targeted design, these magnets can be produced in various shapes and sizes, greatly improving application potential,
• Key role in new technology industries – they find application in data storage devices, electric motors, diagnostic apparatus along with technologically developed systems,
• Relatively small size with high magnetic force – neodymium magnets offer impressive pulling strength in compact dimensions, which makes them ideal in compact constructions

Disadvantages of rare earth magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to physical collisions, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from fracture while also strengthens its overall resistance,
• They lose magnetic force at extreme temperatures. Most neodymium magnets experience permanent loss 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 recommended to use sealed magnets made of plastic for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing fine shapes directly in the magnet,
• Potential hazard due to small fragments may arise, in case of ingestion, which is crucial in the health of young users. Furthermore, minuscule fragments from these devices may complicate medical imaging when ingested,
• Higher purchase price is one of the drawbacks compared to ceramic magnets, especially in budget-sensitive applications

Maximum magnetic pulling force – what affects it?

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

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a smooth surface
• in conditions of no clearance
• with vertical force applied
• at room temperature

Determinants of lifting force in real conditions

Practical lifting force is dependent on factors, 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 performed on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate decreases the lifting capacity.