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

Advantages and disadvantages of neodymium magnets NdFeB.

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

• They retain their attractive force for around 10 years – the drop is just ~1% (based on simulations),
• They protect against demagnetization induced by external magnetic fields very well,
• In other words, due to the shiny silver coating, the magnet obtains an professional appearance,
• They exhibit elevated levels of magnetic induction near the outer area of the magnet,
• Neodymium magnets are known for exceptionally strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the shape),
• The ability for accurate shaping as well as customization to specific needs – neodymium magnets can be manufactured in multiple variants of geometries, which enhances their versatility in applications,
• Wide application in advanced technical fields – they serve a purpose in hard drives, electromechanical systems, diagnostic apparatus or even other advanced devices,
• Compactness – despite their small size, they provide high effectiveness, making them ideal for precision applications

Disadvantages of rare earth magnets:

• They are fragile when subjected to a heavy impact. If the magnets are exposed to external force, they should be placed in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks and strengthens its overall strength,
• Magnets lose pulling force when exposed to temperatures exceeding 80°C. In most cases, this leads to irreversible performance loss (influenced by the magnet’s structure). To address this, we provide [AH] models with superior thermal resistance, able to operate even at 230°C or more,
• They rust in a moist environment – during outdoor use, we recommend using sealed magnets, such as those made of plastic,
• Limited ability to create threads in the magnet – the use of a mechanical support is recommended,
• Health risk linked to microscopic shards may arise, in case of ingestion, which is crucial in the context of child safety. Additionally, miniature parts from these products have the potential to hinder health screening after being swallowed,
• High unit cost – neodymium magnets are more expensive than other types of magnets (e.g., ferrite), which increases the cost of large-scale applications

Optimal lifting capacity of a neodymium magnet – what contributes to it?

The given holding capacity of the magnet means the highest holding force, assessed in the best circumstances, that is:

• with mild steel, serving as a magnetic flux conductor
• with a thickness of minimum 10 mm
• with a smooth surface
• with zero air gap
• with vertical force applied
• at room temperature

Lifting capacity in real conditions – factors

The lifting capacity of a magnet depends on in practice key elements, from primary to secondary:

• Air gap between the magnet and the plate, because even a very small distance (e.g. 0.5 mm) can cause a drop in lifting force of up to 50%.
• Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
• Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
• Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
• Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
• Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under perpendicular forces, whereas under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a small distance {between} the magnet and the plate lowers the lifting capacity.