MPL 15x15x5 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after 10 years, the performance loss is only ~1% (according to literature),
• They protect against demagnetization induced by ambient electromagnetic environments effectively,
• Thanks to the glossy finish and nickel coating, they have an aesthetic appearance,
• The outer field strength of the magnet shows elevated magnetic properties,
• With the right combination of compounds, they reach excellent thermal stability, enabling operation at or above 230°C (depending on the design),
• With the option for tailored forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving design adaptation,
• Important function in new technology industries – they are used in hard drives, rotating machines, clinical machines and other advanced devices,
• Compactness – despite their small size, they deliver powerful magnetism, making them ideal for precision applications

Disadvantages of magnetic elements:

• They can break when subjected to a powerful impact. If the magnets are exposed to mechanical hits, they should be placed in a metal holder. The steel housing, in the form of a holder, protects the magnet from cracks and strengthens its overall strength,
• They lose magnetic force at increased temperatures. Most neodymium magnets experience permanent decline in strength when heated above 80°C (depending on the geometry 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 internal holes in the magnet – the use of a external casing is recommended,
• Possible threat due to small fragments may arise, in case of ingestion, which is important in the context of child safety. It should also be noted that minuscule fragments from these products might complicate medical imaging if inside the body,
• Due to a complex production process, their cost is relatively high,

Breakaway strength of the magnet in ideal conditions – what it depends on?

The given strength of the magnet corresponds to the optimal strength, measured in ideal conditions, that is:

• using a steel plate with low carbon content, acting as a magnetic circuit closure
• of a thickness of at least 10 mm
• with a refined outer layer
• in conditions of no clearance
• under perpendicular detachment force
• at room temperature

Lifting capacity in practice – influencing factors

The lifting capacity of a magnet is determined by in practice the following factors, ordered from most important to least significant:

• Air gap between the magnet and the plate, as 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 was assessed by applying a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under shearing force the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet and the plate reduces the lifting capacity.