MP 25x12.5x5 / N38 - ring magnet

Pros as well as cons of neodymium magnets.

In addition to their long-term stability, neodymium magnets provide the following advantages:

• They have constant strength, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under close interference source,
• By applying a shiny coating of nickel, the element presents an proper look,
• The surface of neodymium magnets generates a unique magnetic field – this is a distinguishing feature,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of detailed modeling as well as adapting to concrete conditions,
• Huge importance in electronics industry – they are utilized in HDD drives, electric motors, precision medical tools, also modern systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Problematic aspects of neodymium magnets: tips and applications.

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding 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.
• Due to limitations in creating nuts and complex shapes in magnets, we propose using a housing - magnetic holder.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, tiny parts of these magnets are able to disrupt the diagnostic process medical after entering the body.
• Due to complex production process, their price is relatively high,

Maximum holding power of the magnet – what it depends on?

The specified lifting capacity refers to the maximum value, obtained under optimal environment, meaning:

• with the use of a sheet made of low-carbon steel, ensuring full magnetic saturation
• whose transverse dimension reaches at least 10 mm
• with a surface cleaned and smooth
• with total lack of distance (without impurities)
• under axial force vector (90-degree angle)
• at ambient temperature room level

What influences lifting capacity in practice

Bear in mind that the working load may be lower influenced by the following factors, starting with the most relevant:

• Gap between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) 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 holding force drops drastically, often to levels of 20-30% of the nominal value.
• Steel thickness – insufficiently thick plate causes magnetic saturation, causing part of the power to be wasted to the other side.
• Material type – ideal substrate is high-permeability steel. Stainless steels may attract less.
• Smoothness – ideal contact is possible only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Thermal factor – high temperature weakens magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity was determined by applying a smooth steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under shearing force the holding force is lower. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.