UMGW 36x18x8 [M8] GW / N38 - magnetic holder internal thread

Pros and cons of rare earth magnets.

Besides their tremendous field intensity, neodymium magnets offer the following advantages:

• They have constant strength, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
• They are extremely resistant to demagnetization induced by external magnetic fields,
• The use of an aesthetic finish of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• They are known for high magnetic induction at the operating surface, which affects their effectiveness,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• Thanks to modularity in shaping and the capacity to adapt to individual projects,
• Huge importance in advanced technology sectors – they are utilized in data components, electric motors, diagnostic systems, and industrial machines.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (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
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• We suggest cover - magnetic mount, due to difficulties in realizing threads inside the magnet and complex forms.
• Health risk resulting from small fragments of magnets pose a threat, in case of ingestion, which gains importance in the context of child safety. It is also worth noting that small components of these magnets can be problematic in diagnostics medical after entering the body.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Best holding force of the magnet in ideal parameters – what it depends on?

The specified lifting capacity concerns the maximum value, measured under ideal test conditions, specifically:

• using a sheet made of high-permeability steel, functioning as a ideal flux conductor
• with a cross-section of at least 10 mm
• with an polished contact surface
• without any clearance between the magnet and steel
• under perpendicular force direction (90-degree angle)
• at temperature approx. 20 degrees Celsius

Practical aspects of lifting capacity – factors

In real-world applications, the actual lifting capacity depends on several key aspects, presented from crucial:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
• Material type – ideal substrate is high-permeability steel. Hardened steels may attract less.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Uneven metal reduce efficiency.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost gain strength (up to a certain limit).

* Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.