AM ucho [M8] - magnetic accessories

Strengths as well as weaknesses of rare earth magnets.

Apart from their consistent holding force, neodymium magnets have these key benefits:

• Their magnetic field is maintained, and after around ten years it drops only by ~1% (according to research),
• They are extremely resistant to demagnetization induced by external field influence,
• A magnet with a shiny silver surface has an effective appearance,
• They are known for high magnetic induction at the operating surface, which improves attraction properties,
• Thanks to resistance to high temperature, they can operate (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of custom shaping as well as optimizing to concrete conditions,
• Versatile presence in advanced technology sectors – they are utilized in HDD drives, motor assemblies, advanced medical instruments, as well as technologically advanced constructions.
• Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its 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.
• Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture
• Due to limitations in creating threads and complicated forms in magnets, we recommend using cover - magnetic holder.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small components of these devices can be problematic in diagnostics medical when they are in the body.
• Due to complex production process, their price is higher than average,

Best holding force of the magnet in ideal parameters – what affects it?

The declared magnet strength refers to the peak performance, obtained under laboratory conditions, specifically:

• with the use of a yoke made of special test steel, guaranteeing maximum field concentration
• possessing a thickness of at least 10 mm to avoid saturation
• with an polished contact surface
• with direct contact (no impurities)
• under perpendicular force direction (90-degree angle)
• at ambient temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

In real-world applications, the actual holding force is determined by many variables, ranked from the most important:

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
• Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
• Plate material – mild steel attracts best. Alloy admixtures reduce magnetic permeability and lifting capacity.
• Surface quality – the more even the plate, the better the adhesion and higher the lifting capacity. Unevenness creates an air distance.
• Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they lose power, and at low temperatures they can be stronger (up to a certain limit).

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the load capacity is reduced by as much as 5 times. Moreover, even a minimal clearance {between} the magnet and the plate decreases the load capacity.