MW 6x6 / N38 - cylindrical magnet

Advantages and disadvantages of rare earth magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• Their magnetic field is maintained, and after around 10 years it decreases only by ~1% (according to research),
• They maintain their magnetic properties even under external field action,
• Thanks to the reflective finish, the coating of nickel, gold, or silver gives an modern appearance,
• Magnets are distinguished by excellent magnetic induction on the active area,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Thanks to the option of accurate forming and customization to custom solutions, neodymium magnets can be manufactured in a broad palette of shapes and sizes, which expands the range of possible applications,
• Fundamental importance in innovative solutions – they are commonly used in mass storage devices, electric motors, medical devices, also industrial machines.
• Thanks to their power density, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• 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 usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited possibility of producing threads in the magnet and complex shapes - recommended is casing - magnet mounting.
• Potential hazard to health – tiny shards of magnets pose a threat, in case of ingestion, which is particularly important in the context of child safety. Furthermore, small elements of these products 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 holding power of the magnet – what contributes to it?

The specified lifting capacity concerns the maximum value, recorded under optimal environment, specifically:

• with the contact of a yoke made of special test steel, guaranteeing full magnetic saturation
• possessing a massiveness of min. 10 mm to ensure full flux closure
• with an polished contact surface
• under conditions of no distance (surface-to-surface)
• under vertical force vector (90-degree angle)
• in neutral thermal conditions

Practical aspects of lifting capacity – factors

Bear in mind that the working load may be lower subject to elements below, in order of importance:

• Gap between magnet and steel – every millimeter of distance (caused e.g. by veneer or dirt) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – declared lifting capacity refers to detachment vertically. When applying parallel force, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Steel thickness – too thin steel causes magnetic saturation, causing part of the power to be lost into the air.
• Chemical composition of the base – low-carbon steel attracts best. Alloy steels reduce magnetic properties and lifting capacity.
• Plate texture – ground elements ensure maximum contact, which improves force. Rough surfaces weaken the grip.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under shearing force the load capacity is reduced by as much as 75%. In addition, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.