UMH 60x15x69 [M8] / N38 - magnetic holder with hook

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have stable power, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They show superior resistance to demagnetization from outside magnetic sources,
• By applying a shiny layer of gold, the element gains a clean look,
• They have exceptional magnetic induction on the surface of the magnet,
• These magnets tolerate extreme temperatures, often exceeding 230°C, when properly designed (in relation to build),
• The ability for custom shaping or adjustment to individual needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Key role in advanced technical fields – they serve a purpose in HDDs, electric drives, medical equipment along with technologically developed systems,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to shocks, it is suggested to place them in a protective case. The steel housing, in the form of a holder, protects the magnet from fracture , and at the same time increases its overall strength,
• They lose power 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 synthetic coating for outdoor use,
• Limited ability to create threads in the magnet – the use of a mechanical support is recommended,
• Health risk from tiny pieces may arise, especially if swallowed, which is notable in the protection of children. Moreover, tiny components from these products have the potential to interfere with diagnostics once in the system,
• Higher purchase price is an important factor to consider compared to ceramic magnets, especially in budget-sensitive applications

Highest magnetic holding force – what affects it?

The given lifting capacity of the magnet means the maximum lifting force, measured in a perfect environment, namely:

• with the use of low-carbon steel plate serving as a magnetic yoke
• having a thickness of no less than 10 millimeters
• with a polished side
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Impact of factors on magnetic holding capacity in practice

Practical lifting force is determined by factors, by priority:

• Air gap between the magnet and the plate, as 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 smooth steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, however under shearing force the load capacity is reduced by as much as fivefold. In addition, even a slight gap {between} the magnet’s surface and the plate decreases the lifting capacity.