MW 5x3 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

Besides their immense field intensity, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• They do not lose their magnetic properties even under close interference source,
• By covering with a smooth layer of nickel, the element presents an elegant look,
• Magnetic induction on the top side of the magnet turns out to be exceptional,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Thanks to the option of accurate forming and adaptation to custom projects, magnetic components can be created in a wide range of geometric configurations, which expands the range of possible applications,
• Universal use in modern technologies – they are utilized in mass storage devices, electric drive systems, diagnostic systems, as well as other advanced devices.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages of neodymium magnets:

• They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
• Neodymium magnets lose their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• We recommend a housing - magnetic holder, due to difficulties in producing nuts inside the magnet and complicated forms.
• Potential hazard resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the context of child safety. Furthermore, tiny parts of these magnets can be problematic in diagnostics medical after entering the body.
• Due to neodymium price, their price exceeds standard values,

Best holding force of the magnet in ideal parameters – what it depends on?

Information about lifting capacity was determined for ideal contact conditions, including:

• with the use of a sheet made of low-carbon steel, ensuring full magnetic saturation
• with a thickness minimum 10 mm
• with a surface perfectly flat
• without any insulating layer between the magnet and steel
• under vertical application of breakaway force (90-degree angle)
• in stable room temperature

Practical aspects of lifting capacity – factors

Holding efficiency is affected by specific conditions, mainly (from most important):

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Angle of force application – highest force is reached only during pulling at a 90° angle. The shear force of the magnet along the surface is typically many times lower (approx. 1/5 of the lifting capacity).
• Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
• Material composition – not every steel attracts identically. High carbon content weaken the interaction with the magnet.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and stronger the hold. Roughness creates an air distance.
• Thermal environment – heating the magnet causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

* Lifting capacity was assessed using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the lifting capacity is smaller. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.