MPL 5x4x1 / N38 - lamellar magnet

Pros as well as cons of rare earth magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They retain magnetic properties for nearly 10 years – the loss is just ~1% (according to analyses),
• They maintain their magnetic properties even under strong external field,
• Thanks to the glossy finish, the surface of Ni-Cu-Ni, gold-plated, or silver-plated gives an modern appearance,
• Magnets are distinguished by excellent magnetic induction on the active area,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Thanks to flexibility in shaping and the ability to modify to specific needs,
• Wide application in modern technologies – they are commonly used in hard drives, electric drive systems, precision medical tools, and other advanced devices.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose 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 magnets in rubber or plastics, which secure oxidation as well as corrosion.
• We recommend a housing - magnetic holder, due to difficulties in realizing nuts inside the magnet and complicated forms.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. It is also worth noting that small elements of these products can be problematic in diagnostics medical when they are in the body.
• Due to complex production process, their price exceeds standard values,

Highest magnetic holding force – what contributes to it?

The specified lifting capacity represents the limit force, measured under ideal test conditions, specifically:

• with the application of a sheet made of low-carbon steel, guaranteeing maximum field concentration
• possessing a thickness of min. 10 mm to avoid saturation
• with a plane cleaned and smooth
• with total lack of distance (without impurities)
• for force applied at a right angle (in the magnet axis)
• at conditions approx. 20°C

Practical lifting capacity: influencing factors

Bear in mind that the magnet holding may be lower influenced by elements below, starting with the most relevant:

• Space between magnet and steel – every millimeter of separation (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – to utilize 100% power, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Metal type – different alloys reacts the same. High carbon content weaken the attraction effect.
• Smoothness – ideal contact is possible only on polished steel. Rough texture create air cushions, weakening the magnet.
• Temperature – temperature increase results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when the force acted perpendicularly, 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.