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

Advantages as well as disadvantages of neodymium magnets.

Besides their durability, neodymium magnets are valued for these benefits:

• They retain full power for nearly 10 years – the drop is just ~1% (according to analyses),
• They feature excellent resistance to magnetic field loss due to external fields,
• A magnet with a smooth nickel surface is more attractive,
• Magnetic induction on the working layer of the magnet turns out to be exceptional,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of exact shaping and adjusting to defined applications,
• Universal use in modern technologies – they are utilized in computer drives, drive modules, medical equipment, as well as complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Problematic aspects of neodymium magnets: application proposals

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in producing nuts and complicated shapes in magnets, we recommend using casing - magnetic mount.
• Potential hazard to health – tiny shards of magnets are risky, in case of ingestion, which is particularly important in the context of child health protection. Furthermore, small elements of these devices are able to be problematic in diagnostics medical in case of swallowing.
• Due to complex production process, their price is higher than average,

Magnetic strength at its maximum – what affects it?

Magnet power is the result of a measurement for ideal contact conditions, taking into account:

• using a sheet made of low-carbon steel, acting as a magnetic yoke
• whose thickness is min. 10 mm
• characterized by smoothness
• under conditions of ideal adhesion (surface-to-surface)
• under perpendicular force vector (90-degree angle)
• at conditions approx. 20°C

Practical aspects of lifting capacity – factors

In practice, the actual holding force results from a number of factors, presented from crucial:

• Clearance – existence of any layer (rust, tape, air) interrupts the magnetic circuit, which lowers capacity rapidly (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick steel does not accept the full field, causing part of the power to be lost into the air.
• Steel grade – the best choice is high-permeability steel. Cast iron may generate lower lifting capacity.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
• Thermal environment – temperature increase results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the holding force is lower. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the holding force.