MW 33x30 / N38 - cylindrical magnet

Strengths and weaknesses of NdFeB magnets.

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

• They retain full power for around ten years – the drop is just ~1% (based on simulations),
• Neodymium magnets are distinguished by extremely resistant to loss of magnetic properties caused by external magnetic fields,
• Thanks to the metallic finish, the coating of nickel, gold, or silver gives an modern appearance,
• The surface of neodymium magnets generates a concentrated magnetic field – this is a key feature,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of custom forming and optimizing to complex requirements,
• Significant place in future technologies – they are used in data components, drive modules, precision medical tools, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which allows their use in miniature devices

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects 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 power. 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, in case of application outdoors
• Limited possibility of making threads in the magnet and complex forms - preferred is casing - magnetic holder.
• Possible danger resulting from small fragments of magnets pose a threat, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these products are able to disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum lifting capacity of the magnet – what affects it?

The lifting capacity listed is a result of laboratory testing executed under specific, ideal conditions:

• with the use of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• whose transverse dimension is min. 10 mm
• characterized by even structure
• without any insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at temperature approx. 20 degrees Celsius

Determinants of practical lifting force of a magnet

In practice, the real power depends on many variables, ranked from the most important:

• Distance (between the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Base massiveness – insufficiently thick steel causes magnetic saturation, causing part of the power to be escaped into the air.
• Material composition – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
• Plate texture – ground elements guarantee perfect abutment, which improves field saturation. Uneven metal weaken the grip.
• Temperature – temperature increase results in weakening of force. Check the thermal limit for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under attempts to slide the magnet the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate lowers the lifting capacity.