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

Advantages and disadvantages of NdFeB magnets.

In addition to their pulling strength, neodymium magnets provide the following advantages:

• They retain full power for almost 10 years – the loss is just ~1% (based on simulations),
• Neodymium magnets are characterized by extremely resistant to demagnetization caused by external magnetic fields,
• A magnet with a shiny gold surface has better aesthetics,
• Neodymium magnets create maximum magnetic induction on a small surface, which increases force concentration,
• 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 accurate shaping and adapting to specific conditions,
• Significant place in electronics industry – they are commonly used in data components, drive modules, medical equipment, also multitasking production systems.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

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

• Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also raises their durability
• Neodymium magnets lose their force 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 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 as well as corrosion.
• Due to limitations in creating threads and complicated forms in magnets, we recommend using cover - magnetic mount.
• Health risk to health – tiny shards of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. It is also worth noting that small elements of these products can disrupt the diagnostic process medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum magnetic pulling force – what affects it?

Information about lifting capacity is the result of a measurement for the most favorable conditions, taking into account:

• on a plate made of structural steel, effectively closing the magnetic flux
• whose transverse dimension equals approx. 10 mm
• with a surface cleaned and smooth
• with zero gap (no coatings)
• during detachment in a direction perpendicular to the plane
• in neutral thermal conditions

Key elements affecting lifting force

In real-world applications, the actual holding force is determined by a number of factors, presented from the most important:

• Air gap (betwixt the magnet and the plate), since even a microscopic distance (e.g. 0.5 mm) leads to a reduction in lifting capacity by up to 50% (this also applies to paint, rust or dirt).
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick plate does not accept the full field, causing part of the power to be escaped into the air.
• Material composition – different alloys attracts identically. High carbon content worsen the attraction effect.
• Surface condition – ground elements guarantee perfect abutment, which increases field saturation. Rough surfaces reduce efficiency.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a slight gap {between} the magnet and the plate lowers the lifting capacity.