MW 15x5 / N38 - cylindrical magnet

Advantages and disadvantages of neodymium magnets NdFeB.

Apart from their consistent magnetism, neodymium magnets have these key benefits:

• 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,
• The use of a polished silver surface provides a eye-catching finish,
• The outer field strength of the magnet shows remarkable magnetic properties,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• The ability for custom shaping or adaptation to custom needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Key role in cutting-edge sectors – they serve a purpose in hard drives, electric motors, diagnostic apparatus or even technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They are fragile when subjected to a strong impact. If the magnets are exposed to mechanical hits, it is advisable to use in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from damage , and at the same time increases its overall durability,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s dimensions). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a wet environment. For outdoor use, we recommend using moisture-resistant magnets, such as those made of plastic,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is difficult,
• Health risk related to magnet particles may arise, especially if swallowed, which is crucial in the health of young users. Furthermore, small elements from these magnets might hinder health screening when ingested,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

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

The given pulling force of the magnet means the maximum force, calculated in the best circumstances, that is:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• with vertical force applied
• in normal thermal conditions

Impact of factors on magnetic holding capacity in practice

The lifting capacity of a magnet is determined by in practice the following factors, according to their importance:

• 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 was determined by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance {between} the magnet and the plate reduces the load capacity.