MPL 40x18x10 SH / N38 - lamellar magnet

Pros and cons of neodymium magnets.

Besides their exceptional strength, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after 10 years the performance loss is only ~1% (according to literature),
• They are extremely resistant to demagnetization induced by external field influence,
• By covering with a lustrous coating of gold, the element gains an nice look,
• Magnetic induction on the working part of the magnet remains exceptional,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Due to the ability of precise forming and adaptation to specialized needs, NdFeB magnets can be created in a variety of geometric configurations, which expands the range of possible applications,
• Huge importance in high-tech industry – they serve a role in magnetic memories, motor assemblies, medical equipment, also industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as those in rubber or plastics, which prevent oxidation as well as corrosion.
• Limited ability of creating threads in the magnet and complicated shapes - recommended is cover - magnet mounting.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which becomes key in the context of child health protection. Furthermore, tiny parts of these magnets are able to be problematic in diagnostics medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what contributes to it?

Holding force of 0 kg is a measurement result conducted under standard conditions:

• using a sheet made of high-permeability steel, acting as a circuit closing element
• possessing a massiveness of min. 10 mm to avoid saturation
• characterized by lack of roughness
• under conditions of no distance (metal-to-metal)
• during pulling in a direction vertical to the mounting surface
• at standard ambient temperature

Determinants of lifting force in real conditions

Effective lifting capacity is affected by working environment parameters, mainly (from most important):

• Distance (between the magnet and the plate), as even a tiny clearance (e.g. 0.5 mm) can cause a decrease in force by up to 50% (this also applies to paint, corrosion or dirt).
• Load vector – highest force is reached only during perpendicular pulling. The force required to slide of the magnet along the plate is standardly many times lower (approx. 1/5 of the lifting capacity).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of generating force.
• Plate material – mild steel attracts best. Alloy steels lower magnetic properties and lifting capacity.
• Surface finish – ideal contact is obtained only on polished steel. Rough texture create air cushions, reducing force.
• Temperature influence – hot environment weakens magnetic field. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.