MPL 5x5x1.5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They retain their magnetic properties for nearly ten years – the drop is just ~1% (in theory),
• They remain magnetized despite exposure to magnetic noise,
• Thanks to the shiny finish and gold coating, they have an visually attractive appearance,
• The outer field strength of the magnet shows remarkable 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 numerous shapes and sizes, greatly improving design adaptation,
• Wide application in advanced technical fields – they are utilized in computer drives, rotating machines, diagnostic apparatus or even technologically developed systems,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• They may fracture when subjected to a heavy impact. If the magnets are exposed to physical collisions, we recommend in a protective enclosure. The steel housing, in the form of a holder, protects the magnet from breakage , and at the same time increases its overall strength,
• They lose power at increased temperatures. Most neodymium magnets experience permanent decline 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 wet environment. For outdoor use, we recommend using encapsulated magnets, such as those made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing threads directly in the magnet,
• Health risk related to magnet particles may arise, especially if swallowed, which is crucial in the context of child safety. Furthermore, tiny components from these magnets might complicate medical imaging if inside the body,
• In cases of mass production, neodymium magnet cost is a challenge,

Best holding force of the magnet in ideal parameters – what affects it?

The given lifting capacity of the magnet corresponds to the maximum lifting force, calculated in a perfect environment, specifically:

• with mild steel, used as a magnetic flux conductor
• 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

What influences lifting capacity in practice

In practice, the holding capacity of a magnet is affected by the following aspects, 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) 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 with the use of a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, in contrast under parallel forces the holding force is lower. In addition, even a minimal clearance {between} the magnet and the plate reduces the load capacity.