UMT 20x25 black / N38 - board holder

Pros and cons of NdFeB magnets.

Apart from their superior power, neodymium magnets have these key benefits:

• 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 loss of magnetic properties caused by external interference,
• By using a shiny coating of silver, the element acquires an modern look,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of individual machining as well as modifying to precise conditions,
• Versatile presence in modern technologies – they find application in HDD drives, brushless drives, advanced medical instruments, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in tiny dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 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 and corrosion.
• We suggest a housing - magnetic mechanism, due to difficulties in realizing threads inside the magnet and complicated forms.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small components of these devices are able to be problematic in diagnostics medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Maximum holding power of the magnet – what affects it?

The load parameter shown represents the limit force, obtained under ideal test conditions, specifically:

• with the application of a yoke made of special test steel, ensuring full magnetic saturation
• whose thickness equals approx. 10 mm
• characterized by lack of roughness
• with total lack of distance (without impurities)
• under vertical force direction (90-degree angle)
• at temperature room level

Key elements affecting lifting force

It is worth knowing that the application force will differ influenced by elements below, in order of importance:

• Air gap (betwixt the magnet and the plate), as even a tiny distance (e.g. 0.5 mm) results in a drastic drop in force by up to 50% (this also applies to paint, corrosion or dirt).
• Direction of force – highest force is available only during pulling at a 90° angle. The force required to slide of the magnet along the plate is standardly many times smaller (approx. 1/5 of the lifting capacity).
• Element thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Alloy admixtures lower magnetic permeability and lifting capacity.
• Surface quality – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
• Thermal environment – temperature increase causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under perpendicular forces, in contrast under shearing force the load capacity is reduced by as much as fivefold. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.