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

Pros and cons of NdFeB magnets.

Besides their immense strength, neodymium magnets offer the following advantages:

• They have unchanged lifting capacity, and over nearly ten years their attraction force decreases symbolically – ~1% (in testing),
• They maintain their magnetic properties even under external field action,
• The use of an aesthetic coating of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Neodymium magnets achieve maximum magnetic induction on a their surface, which allows for strong attraction,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Thanks to versatility in constructing and the ability to modify to specific needs,
• Universal use in modern technologies – they are used in hard drives, drive modules, advanced medical instruments, and industrial machines.
• Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in compact dimensions, which enables their usage in compact constructions

What to avoid - cons of neodymium magnets: tips and applications.

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can rust. Therefore while using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in creating threads and complicated shapes in magnets, we recommend using a housing - magnetic holder.
• Potential hazard to health – tiny shards of magnets are risky, in case of ingestion, which becomes key in the context of child health protection. It is also worth noting that small elements of these products can be problematic in diagnostics medical in case of swallowing.
• Due to neodymium price, their price exceeds standard values,

Maximum holding power of the magnet – what affects it?

The declared magnet strength refers to the limit force, obtained under laboratory conditions, specifically:

• with the application of a sheet made of low-carbon steel, ensuring maximum field concentration
• whose transverse dimension is min. 10 mm
• with a surface cleaned and smooth
• with direct contact (no impurities)
• during detachment in a direction perpendicular to the plane
• at ambient temperature room level

Key elements affecting lifting force

Bear in mind that the working load will differ influenced by elements below, starting with the most relevant:

• Distance – the presence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When applying parallel force, the magnet exhibits much less (often approx. 20-30% of maximum force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Material composition – not every steel reacts the same. Alloy additives weaken the attraction effect.
• Surface quality – the more even the plate, the better the adhesion and stronger the hold. Unevenness creates an air distance.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under perpendicular forces, in contrast under shearing force the lifting capacity is smaller. In addition, even a small distance {between} the magnet’s surface and the plate decreases the holding force.