MPL 20x20x20 / N38 - lamellar magnet

Advantages as well as disadvantages of neodymium magnets.

Besides their exceptional magnetic power, neodymium magnets offer the following advantages:

• They have constant strength, and over more than 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Magnets very well defend themselves against loss of magnetization caused by external fields,
• Thanks to the elegant finish, the coating of Ni-Cu-Ni, gold, or silver-plated gives an clean appearance,
• Magnetic induction on the working part of the magnet turns out to be exceptional,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Considering the ability of flexible shaping and customization to unique solutions, magnetic components can be modeled in a variety of forms and dimensions, which expands the range of possible applications,
• Huge importance in advanced technology sectors – they are used in data components, motor assemblies, medical devices, also technologically advanced constructions.
• Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in compact dimensions, which enables their usage in miniature devices

Problematic aspects of neodymium magnets: weaknesses and usage proposals

• Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• When exposed to humidity, magnets start to rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• We recommend casing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complex shapes.
• Health risk to health – tiny shards of magnets pose a threat, when accidentally swallowed, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these magnets are able to disrupt the diagnostic process medical after entering the body.
• Due to expensive raw materials, their price is relatively high,

Maximum lifting force for a neodymium magnet – what contributes to it?

The force parameter is a result of laboratory testing performed under specific, ideal conditions:

• using a sheet made of low-carbon steel, acting as a circuit closing element
• with a thickness minimum 10 mm
• with an ground touching surface
• under conditions of ideal adhesion (metal-to-metal)
• under vertical force direction (90-degree angle)
• at ambient temperature room level

Determinants of practical lifting force of a magnet

In real-world applications, the actual holding force is determined by a number of factors, presented from the most important:

• Gap (betwixt the magnet and the metal), as even a microscopic distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Plate thickness – insufficiently thick sheet does not close the flux, causing part of the power to be wasted to the other side.
• Material type – the best choice is high-permeability steel. Stainless steels may have worse magnetic properties.
• Smoothness – full contact is possible only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Thermal environment – temperature increase causes a temporary drop of induction. Check the maximum operating temperature for a given model.

* Lifting capacity was determined with the use of a polished steel plate of optimal thickness (min. 20 mm), under vertically applied force, whereas under attempts to slide the magnet the lifting capacity is smaller. In addition, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.