MPL 5x5x1.5 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets.

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

• They do not lose strength, even during approximately 10 years – the drop in lifting capacity is only ~1% (based on measurements),
• Magnets very well protect themselves against loss of magnetization caused by external fields,
• A magnet with a smooth silver surface is more attractive,
• They feature high magnetic induction at the operating surface, which improves attraction properties,
• 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...
• Possibility of individual machining and modifying to specific applications,
• Key role in modern technologies – they are utilized in hard drives, drive modules, precision medical tools, as well as industrial machines.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 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 creating threads in the magnet and complex shapes - recommended is casing - mounting mechanism.
• Possible danger resulting from small fragments of magnets can be dangerous, in case of ingestion, which gains importance in the context of child safety. Additionally, small components of these products are able to disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum holding power of the magnet – what contributes to it?

The specified lifting capacity represents the maximum value, obtained under laboratory conditions, meaning:

• on a plate made of structural steel, perfectly concentrating the magnetic field
• with a thickness minimum 10 mm
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• during detachment in a direction perpendicular to the mounting surface
• at ambient temperature room level

Practical lifting capacity: influencing factors

During everyday use, the actual holding force depends on many variables, listed from most significant:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick plate causes magnetic saturation, causing part of the power to be escaped to the other side.
• Chemical composition of the base – mild steel gives the best results. Higher carbon content decrease magnetic properties and lifting capacity.
• Plate texture – ground elements guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Temperature – temperature increase causes a temporary drop of induction. Check the thermal limit for a given model.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate lowers the holding force.