MW 8x15 / N38 - cylindrical magnet

Advantages and disadvantages of rare earth magnets.

Besides their remarkable pulling force, neodymium magnets offer the following advantages:

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (according to theory),
• Magnets very well defend themselves against demagnetization caused by ambient magnetic noise,
• In other words, due to the shiny layer of nickel, the element becomes visually attractive,
• They show high magnetic induction at the operating surface, making them more effective,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Thanks to flexibility in designing and the ability to modify to client solutions,
• Significant place in advanced technology sectors – they find application in hard drives, motor assemblies, medical devices, also complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Problematic aspects of neodymium magnets: tips and applications.

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their power 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 stability 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 secure oxidation and corrosion.
• We suggest a housing - magnetic mechanism, due to difficulties in creating nuts inside the magnet and complex shapes.
• Possible danger related to microscopic parts of magnets are risky, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small components of these magnets can disrupt the diagnostic process medical when they are in the body.
• With budget limitations the cost of neodymium magnets is a challenge,

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

The load parameter shown concerns the maximum value, obtained under laboratory conditions, meaning:

• with the use of a sheet made of special test steel, ensuring maximum field concentration
• possessing a massiveness of min. 10 mm to avoid saturation
• with a plane perfectly flat
• with zero gap (without coatings)
• under perpendicular force direction (90-degree angle)
• at standard ambient temperature

Practical lifting capacity: influencing factors

Please note that the working load may be lower subject to the following factors, in order of importance:

• Air gap (between the magnet and the plate), as even a microscopic clearance (e.g. 0.5 mm) leads to a decrease in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick steel does not accept the full field, causing part of the power to be wasted to the other side.
• Chemical composition of the base – mild steel attracts best. Higher carbon content reduce magnetic permeability and holding force.
• Surface finish – full contact is possible only on polished steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal factor – high temperature reduces pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.