HH 25x7.7 [M5] / N38 - through hole magnetic holder

Advantages as well as disadvantages of NdFeB magnets.

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

• They virtually do not lose power, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• They retain their magnetic properties even under external field action,
• The use of an aesthetic finish of noble metals (nickel, gold, silver) causes the element to have aesthetics,
• Magnetic induction on the top side of the magnet is exceptional,
• Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
• Considering the option of precise shaping and adaptation to specialized requirements, magnetic components can be modeled in a variety of geometric configurations, which amplifies use scope,
• Huge importance in high-tech industry – they serve a role in computer drives, motor assemblies, precision medical tools, and modern systems.
• Compactness – despite small sizes they provide effective action, making them ideal for precision applications

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

• At strong impacts they can break, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. To use them in conditions outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation and corrosion.
• Due to limitations in realizing nuts and complicated shapes in magnets, we propose using casing - magnetic holder.
• Possible danger related to microscopic parts of magnets are risky, in case of ingestion, which is particularly important in the context of child safety. Additionally, tiny parts of these magnets can complicate diagnosis medical after entering the body.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what affects it?

The lifting capacity listed is a measurement result performed under specific, ideal conditions:

• with the application of a yoke made of special test steel, guaranteeing maximum field concentration
• possessing a massiveness of min. 10 mm to ensure full flux closure
• with a surface cleaned and smooth
• under conditions of no distance (surface-to-surface)
• during pulling in a direction vertical to the plane
• at ambient temperature room level

Determinants of practical lifting force of a magnet

In real-world applications, the real power depends on many variables, listed from most significant:

• Distance (betwixt the magnet and the plate), as even a very small distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet limits the attraction force (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Alloy admixtures decrease magnetic properties and lifting capacity.
• Smoothness – ideal contact is possible only on polished steel. Any scratches and bumps create air cushions, weakening the magnet.
• Heat – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was determined with the use of a steel plate with a smooth surface of suitable thickness (min. 20 mm), under vertically applied force, however under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the holding force.