MW 8x8 / N38 - cylindrical magnet

Advantages as well as disadvantages of neodymium magnets.

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

• They virtually do not lose power, because even after ten years the performance loss is only ~1% (based on calculations),
• Neodymium magnets remain extremely resistant to demagnetization caused by external field sources,
• Thanks to the elegant finish, the plating of Ni-Cu-Ni, gold-plated, or silver-plated gives an modern appearance,
• Magnets have impressive magnetic induction on the outer layer,
• Through (appropriate) combination of ingredients, they can achieve high thermal resistance, allowing for functioning at temperatures reaching 230°C and above...
• Considering the ability of flexible molding and customization to unique projects, NdFeB magnets can be modeled in a wide range of shapes and sizes, which makes them more universal,
• Wide application in modern technologies – they are used in hard drives, electric motors, precision medical tools, and industrial machines.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets and ways of using them

• To avoid cracks under impact, we recommend using special steel housings. Such a solution protects 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 power decreases (depending on the size and 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 start to 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 complicated forms - recommended is a housing - mounting mechanism.
• Health risk resulting from small fragments of magnets are risky, in case of ingestion, which is particularly important in the aspect of protecting the youngest. Additionally, small elements of these devices are able to disrupt the diagnostic process medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what contributes to it?

Breakaway force is the result of a measurement for ideal contact conditions, assuming:

• using a sheet made of low-carbon steel, serving as a ideal flux conductor
• whose transverse dimension reaches at least 10 mm
• with a plane cleaned and smooth
• without the slightest air gap between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• in stable room temperature

Practical lifting capacity: influencing factors

During everyday use, the real power depends on many variables, ranked from crucial:

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – catalog parameter refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (often approx. 20-30% of maximum force).
• Wall thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of converting into lifting capacity.
• Metal type – different alloys attracts identically. Alloy additives worsen the attraction effect.
• Smoothness – ideal contact is possible only on smooth steel. Any scratches and bumps reduce the real contact area, weakening the magnet.
• Heat – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity was assessed with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular detachment force, in contrast under shearing force the load capacity is reduced by as much as 5 times. In addition, even a small distance {between} the magnet’s surface and the plate lowers the lifting capacity.