BM 380x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of rare earth magnets.

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

• They retain attractive force for nearly ten years – the loss is just ~1% (according to analyses),
• They feature excellent resistance to magnetism drop as a result of external magnetic sources,
• A magnet with a smooth silver surface looks better,
• Magnets have extremely high magnetic induction on the surface,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
• Considering the potential of free shaping and customization to custom solutions, neodymium magnets can be modeled in a broad palette of geometric configurations, which increases their versatility,
• Wide application in innovative solutions – they are utilized in hard drives, electric drive systems, medical devices, also complex engineering applications.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Characteristics of disadvantages of neodymium magnets and ways of using them

• They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• They oxidize in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
• Due to limitations in producing threads and complicated shapes in magnets, we propose using cover - magnetic holder.
• Potential hazard related to microscopic parts of magnets are risky, if swallowed, which gains importance in the context of child safety. Additionally, small components of these magnets are able to complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities

Breakaway strength of the magnet in ideal conditions – what affects it?

Breakaway force is the result of a measurement for optimal configuration, assuming:

• on a plate made of structural steel, optimally conducting the magnetic flux
• whose transverse dimension reaches at least 10 mm
• with a plane free of scratches
• without any air gap between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at conditions approx. 20°C

Impact of factors on magnetic holding capacity in practice

Holding efficiency is influenced by specific conditions, mainly (from most important):

• Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Plate material – low-carbon steel gives the best results. Alloy steels decrease magnetic properties and lifting capacity.
• Base smoothness – the smoother and more polished the surface, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
• 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).

* Lifting capacity was assessed by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, whereas under parallel forces the lifting capacity is smaller. Additionally, even a slight gap {between} the magnet and the plate decreases the holding force.