UMGZ 20x15x7 [M4] GZ / N38 - magnetic holder external thread

Pros and cons of rare earth magnets.

Apart from their strong holding force, neodymium magnets have these key benefits:

• They retain attractive force for around 10 years – the drop is just ~1% (based on simulations),
• Neodymium magnets are remarkably resistant to loss of magnetic properties caused by external interference,
• A magnet with a shiny silver surface looks better,
• Magnetic induction on the working part of the magnet remains maximum,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
• Considering the option of accurate forming and customization to unique projects, magnetic components can be created in a variety of geometric configurations, which increases their versatility,
• Key role in advanced technology sectors – they serve a role in hard drives, drive modules, medical devices, as well as other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in small dimensions, which allows their use in small systems

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• Neodymium magnets decrease their power under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• When exposed to humidity, magnets start to rust. For applications 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 threads and complex forms in magnets, we recommend using casing - magnetic mount.
• Health risk related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the aspect of protecting the youngest. Furthermore, small elements of these products are able to disrupt the diagnostic process medical when they are in the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Breakaway strength of the magnet in ideal conditions – what it depends on?

The lifting capacity listed is a measurement result executed under standard conditions:

• on a base made of structural steel, optimally conducting the magnetic flux
• whose thickness equals approx. 10 mm
• with a surface perfectly flat
• under conditions of ideal adhesion (metal-to-metal)
• during detachment in a direction perpendicular to the plane
• at ambient temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

During everyday use, the actual lifting capacity is determined by a number of factors, ranked from most significant:

• Gap between surfaces – every millimeter of distance (caused e.g. by veneer or dirt) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
• Load vector – maximum parameter is available only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly many times lower (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel type – mild steel attracts best. Higher carbon content lower magnetic properties and lifting capacity.
• Surface finish – full contact is obtained only on polished steel. Rough texture create air cushions, weakening the magnet.
• Operating temperature – neodymium magnets have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was measured on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the holding force is lower. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the lifting capacity.