MPL 30x5x5 / N38 - lamellar magnet

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They do not lose their power around 10 years – the reduction of lifting capacity is only ~1% (according to tests),
• They protect against demagnetization induced by ambient magnetic fields effectively,
• The use of a polished nickel surface provides a refined finish,
• The outer field strength of the magnet shows remarkable magnetic properties,
• Thanks to their enhanced temperature resistance, they can operate (depending on the form) even at temperatures up to 230°C or more,
• Thanks to the flexibility in shaping and the capability to adapt to specific requirements, neodymium magnets can be created in diverse shapes and sizes, which increases their usage potential,
• Important function in cutting-edge sectors – they are utilized in HDDs, electric drives, healthcare devices along with sophisticated instruments,
• Compactness – despite their small size, they generate strong force, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They may fracture when subjected to a powerful impact. If the magnets are exposed to external force, we recommend in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks while also enhances its overall resistance,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible magnetic decay (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,
• Due to corrosion risk in humid conditions, it is wise to use sealed magnets made of synthetic coating for outdoor use,
• Using a cover – such as a magnetic holder – is advised due to the limitations in manufacturing threads directly in the magnet,
• Health risk linked to microscopic shards may arise, especially if swallowed, which is important in the context of child safety. Additionally, tiny components from these devices might interfere with diagnostics when ingested,
• In cases of tight budgets, neodymium magnet cost is a challenge,

Maximum holding power of the magnet – what affects it?

The given lifting capacity of the magnet means the maximum lifting force, calculated under optimal conditions, namely:

• with mild steel, used as a magnetic flux conductor
• having a thickness of no less than 10 millimeters
• with a refined outer layer
• in conditions of no clearance
• with vertical force applied
• under standard ambient temperature

Impact of factors on magnetic holding capacity in practice

Practical lifting force is dependent on elements, by priority:

• 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 smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, however under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate lowers the holding force.