MW 5x15 / N38 - cylindrical magnet

Advantages and disadvantages of NdFeB magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• They retain full power for around ten years – the loss is just ~1% (in theory),
• Neodymium magnets remain extremely resistant to loss of magnetic properties caused by external field sources,
• Thanks to the reflective finish, the coating of Ni-Cu-Ni, gold-plated, or silver gives an professional appearance,
• The surface of neodymium magnets generates a powerful magnetic field – this is one of their assets,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Possibility of custom machining as well as adapting to complex needs,
• Versatile presence in modern industrial fields – they serve a role in magnetic memories, electromotive mechanisms, precision medical tools, also other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Drawbacks and weaknesses of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets decrease 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
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation and corrosion.
• We suggest casing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex forms.
• Possible danger resulting from small fragments of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Additionally, small components of these magnets can disrupt the diagnostic process medical when they are in the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum magnetic pulling force – what contributes to it?

Information about lifting capacity is the result of a measurement for optimal configuration, taking into account:

• using a base made of mild steel, serving as a circuit closing element
• with a thickness of at least 10 mm
• with an ideally smooth touching surface
• without the slightest insulating layer between the magnet and steel
• for force acting at a right angle (pull-off, not shear)
• at conditions approx. 20°C

Key elements affecting lifting force

Please note that the application force will differ influenced by elements below, starting with the most relevant:

• Gap between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Loading method – declared lifting capacity refers to detachment vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Steel thickness – too thin plate causes magnetic saturation, causing part of the flux to be escaped into the air.
• Chemical composition of the base – low-carbon steel attracts best. Alloy steels decrease magnetic permeability and lifting capacity.
• Surface condition – ground elements guarantee perfect abutment, which improves field saturation. Uneven metal reduce efficiency.
• Thermal factor – hot environment reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined by applying a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the holding force is lower. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.