MW 4x10 / N38 - cylindrical magnet

Pros as well as cons of NdFeB magnets.

Apart from their strong magnetism, neodymium magnets have these key benefits:

• They have unchanged lifting capacity, and over around 10 years their performance decreases symbolically – ~1% (according to theory),
• Neodymium magnets prove to be remarkably resistant to demagnetization caused by external interference,
• In other words, due to the metallic layer of gold, the element becomes visually attractive,
• Neodymium magnets deliver maximum magnetic induction on a their surface, which allows for strong attraction,
• Through (adequate) combination of ingredients, they can achieve high thermal strength, allowing for operation at temperatures reaching 230°C and above...
• Thanks to modularity in shaping and the capacity to customize to individual projects,
• Fundamental importance in electronics industry – they are commonly used in mass storage devices, electromotive mechanisms, medical devices, and multitasking production systems.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which allows their use in compact constructions

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They oxidize in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We suggest casing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the context of child safety. Additionally, tiny parts of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum lifting capacity of the magnet – what it depends on?

The specified lifting capacity concerns the maximum value, recorded under ideal test conditions, namely:

• on a block made of mild steel, optimally conducting the magnetic flux
• whose thickness is min. 10 mm
• with an ideally smooth touching surface
• with direct contact (no paint)
• under vertical force direction (90-degree angle)
• at temperature room level

Practical lifting capacity: influencing factors

During everyday use, the actual lifting capacity results from several key aspects, listed from most significant:

• Space between surfaces – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the magnet efficiency, often by half at just 0.5 mm.
• Direction of force – maximum parameter is reached only during perpendicular pulling. The resistance to sliding of the magnet along the surface is standardly several times smaller (approx. 1/5 of the lifting capacity).
• Plate thickness – too thin sheet causes magnetic saturation, causing part of the flux to be escaped into the air.
• Metal type – not every steel reacts the same. High carbon content weaken the interaction with the magnet.
• Base smoothness – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Temperature influence – high temperature weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under attempts to slide the magnet the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate reduces the lifting capacity.