MW 16x9 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for around ten years – the drop is just ~1% (based on simulations),
• They protect against demagnetization induced by surrounding magnetic fields remarkably well,
• Because of the reflective layer of nickel, the component looks high-end,
• They exhibit extremely high levels of magnetic induction near the outer area of the magnet,
• They are suitable for high-temperature applications, operating effectively at 230°C+ due to advanced heat resistance and form-specific properties,
• The ability for custom shaping or adaptation to individual needs – neodymium magnets can be manufactured in many forms and dimensions, which amplifies their functionality across industries,
• Key role in new technology industries – they are utilized in computer drives, electric drives, diagnostic apparatus or even high-tech tools,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, with minimal size,

Disadvantages of neodymium magnets:

• They are prone to breaking when subjected to a powerful impact. If the magnets are exposed to shocks, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from damage and additionally enhances its overall strength,
• They lose field intensity at increased temperatures. Most neodymium magnets experience permanent degradation 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,
• They rust in a humid environment. If exposed to rain, we recommend using sealed magnets, such as those made of rubber,
• Limited ability to create precision features in the magnet – the use of a mechanical support is recommended,
• Health risk linked to microscopic shards may arise, especially if swallowed, which is important in the health of young users. It should also be noted that miniature parts from these assemblies might disrupt scanning when ingested,
• High unit cost – neodymium magnets are costlier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

Detachment force of the magnet in optimal conditions – what it depends on?

The given holding capacity of the magnet corresponds to the highest holding force, calculated in ideal conditions, that is:

• with mild steel, used as a magnetic flux conductor
• of a thickness of at least 10 mm
• with a refined outer layer
• with zero air gap
• with vertical force applied
• in normal thermal conditions

Lifting capacity in real conditions – factors

In practice, the holding capacity of a magnet is affected by these factors, arranged from the most important to the least relevant:

• Air gap between the magnet and the plate, since 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 carried out on a smooth plate of suitable thickness, under perpendicular forces, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate lowers the lifting capacity.