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

Advantages and disadvantages of neodymium magnets NdFeB.

Besides their durability, neodymium magnets are valued for these benefits:

• They do not lose their even during approximately ten years – the reduction of strength is only ~1% (based on measurements),
• Their ability to resist magnetic interference from external fields is among the best,
• The use of a mirror-like nickel surface provides a refined finish,
• Magnetic induction on the surface of these magnets is very strong,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the geometry),
• The ability for precise shaping and adjustment to specific needs – neodymium magnets can be manufactured in a wide range of shapes and sizes, which enhances their versatility in applications,
• Significant impact in advanced technical fields – they serve a purpose in hard drives, rotating machines, clinical machines along with high-tech tools,
• Thanks to their efficiency per volume, small magnets offer high magnetic performance, with minimal size,

Disadvantages of neodymium magnets:

• They may fracture when subjected to a strong impact. If the magnets are exposed to shocks, we recommend in a metal holder. The steel housing, in the form of a holder, protects the magnet from fracture while also strengthens its overall strength,
• They lose field intensity at elevated 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,
• Magnets exposed to humidity can degrade. Therefore, for outdoor applications, we advise waterproof types made of plastic,
• Using a cover – such as a magnetic holder – is advised due to the challenges in manufacturing complex structures directly in the magnet,
• Potential hazard due to small fragments may arise, in case of ingestion, which is notable in the health of young users. It should also be noted that minuscule fragments from these assemblies can hinder health screening after being swallowed,
• High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Maximum lifting force for a neodymium magnet – what it depends on?

The given holding capacity of the magnet corresponds to the highest holding force, calculated in ideal conditions, namely:

• using a steel plate with low carbon content, serving as a magnetic circuit closure
• with a thickness of minimum 10 mm
• with a refined outer layer
• with no separation
• in a perpendicular direction of force
• under standard ambient temperature

Lifting capacity in real conditions – factors

Practical lifting force is determined by factors, listed from the most critical to the less 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.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, in contrast under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet and the plate lowers the load capacity.