UMGB 75x28 [M10x3] GW F200 GOLD +Lina GOBLIN / N42 - goblin magnetic holder

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their high retention, neodymium magnets are valued for these benefits:

• They retain their attractive force for around 10 years – the drop is just ~1% (according to analyses),
• They protect against demagnetization induced by surrounding magnetic influence effectively,
• By applying a reflective layer of silver, the element gains a sleek look,
• They possess significant magnetic force measurable at the magnet’s surface,
• Thanks to their enhanced temperature resistance, they can operate (depending on the geometry) even at temperatures up to 230°C or more,
• Thanks to the freedom in shaping and the capability to adapt to individual requirements, neodymium magnets can be created in different geometries, which increases their application range,
• Wide application in cutting-edge sectors – they find application in HDDs, electromechanical systems, healthcare devices along with high-tech tools,
• Thanks to their concentrated strength, small magnets offer high magnetic performance, while occupying minimal space,

Disadvantages of NdFeB magnets:

• They are fragile when subjected to a strong impact. If the magnets are exposed to external force, it is advisable to use in a protective case. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time increases its overall robustness,
• High temperatures may significantly reduce the magnetic power of neodymium magnets. Typically, above 80°C, they experience permanent weakening in performance (depending on size). To prevent this, we offer heat-resistant magnets marked [AH], capable of working up to 230°C, which makes them perfect for high-temperature use,
• Magnets exposed to damp air can oxidize. Therefore, for outdoor applications, we suggest waterproof types made of plastic,
• Limited ability to create complex details in the magnet – the use of a mechanical support is recommended,
• Potential hazard related to magnet particles may arise, in case of ingestion, which is significant in the context of child safety. Additionally, miniature parts from these devices can complicate medical imaging if inside the body,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which can restrict large-scale applications

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

The given lifting capacity of the magnet means the maximum lifting force, determined in the best circumstances, specifically:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a refined outer layer
• with zero air gap
• in a perpendicular direction of force
• in normal thermal conditions

Key elements affecting lifting force

Practical lifting force is dependent on factors, listed from the most critical to the less significant:

• Air gap between the magnet and the plate, because 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.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.