BM 700x180x75 [8xM10] - magnetic beam

Pros and cons of neodymium magnets.

Apart from their notable magnetic energy, neodymium magnets have these key benefits:

• They do not lose magnetism, even over approximately ten years – the decrease in power is only ~1% (according to tests),
• Magnets effectively resist against demagnetization caused by foreign field sources,
• A magnet with a shiny nickel surface has an effective appearance,
• The surface of neodymium magnets generates a intense magnetic field – this is a key feature,
• 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...
• Thanks to flexibility in shaping and the ability to customize to complex applications,
• Fundamental importance in advanced technology sectors – they are used in HDD drives, drive modules, diagnostic systems, as well as complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, occupying minimum space,

Cons of neodymium magnets and proposals for their use:

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
• Neodymium magnets decrease their power 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 stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of producing nuts in the magnet and complicated shapes - preferred is a housing - magnetic holder.
• Possible danger related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small elements of these devices are able to be problematic in diagnostics medical when they are in the body.
• With budget limitations the cost of neodymium magnets can be a barrier,

Maximum holding power of the magnet – what contributes to it?

The force parameter is a theoretical maximum value performed under standard conditions:

• with the use of a yoke made of special test steel, ensuring full magnetic saturation
• whose transverse dimension reaches at least 10 mm
• with a surface perfectly flat
• with zero gap (without coatings)
• for force acting at a right angle (in the magnet axis)
• in stable room temperature

Lifting capacity in real conditions – factors

In real-world applications, the actual holding force results from a number of factors, ranked from most significant:

• Clearance – the presence of foreign body (rust, dirt, gap) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• 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 – different alloys attracts identically. High carbon content worsen the interaction with the magnet.
• Surface structure – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
• Temperature influence – hot environment reduces pulling force. Too high temperature can permanently damage the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.