MPL 35x35x10 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They have stable power, and over around ten years their performance decreases symbolically – ~1% (in testing),
• They show strong resistance to demagnetization from external field exposure,
• The use of a mirror-like silver surface provides a smooth finish,
• They exhibit elevated 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,
• With the option for fine forming and personalized design, these magnets can be produced in various shapes and sizes, greatly improving engineering flexibility,
• Key role in cutting-edge sectors – they are used in data storage devices, electric motors, clinical machines along with sophisticated instruments,
• Relatively small size with high magnetic force – neodymium magnets offer intense magnetic field in tiny dimensions, which makes them useful in compact constructions

Disadvantages of magnetic elements:

• They are fragile when subjected to a powerful impact. If the magnets are exposed to mechanical hits, it is suggested to place them in a metal holder. The steel housing, in the form of a holder, protects the magnet from damage and additionally enhances its overall durability,
• Magnets lose magnetic efficiency when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible field weakening (influenced by the magnet’s profile). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• Magnets exposed to damp air can rust. Therefore, for outdoor applications, we advise waterproof types made of plastic,
• The use of a protective casing or external holder is recommended, since machining multi-axis shapes in neodymium magnets is risky,
• Possible threat due to small fragments may arise, when consumed by mistake, which is crucial in the health of young users. Furthermore, tiny components from these magnets may disrupt scanning if inside the body,
• In cases of mass production, neodymium magnet cost is a challenge,

Highest magnetic holding force – what affects it?

The given lifting capacity of the magnet represents the maximum lifting force, calculated in ideal conditions, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• 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

Determinants of lifting force in real conditions

Practical lifting force is determined by factors, by priority:

• 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.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap {between} the magnet and the plate reduces the lifting capacity.