BM 320x180x70 [4x M8] - magnetic beam

Strengths and weaknesses of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose power, because even after ten years the decline in efficiency is only ~1% (according to literature),
• Magnets perfectly protect themselves against loss of magnetization caused by external fields,
• In other words, due to the smooth finish of gold, the element is aesthetically pleasing,
• Magnetic induction on the top side of the magnet remains very high,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Possibility of custom forming and modifying to specific needs,
• Huge importance in modern technologies – they serve a role in magnetic memories, motor assemblies, advanced medical instruments, as well as industrial machines.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• At strong impacts they can break, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we advise our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material immune to moisture, in case of application outdoors
• We suggest a housing - magnetic mount, due to difficulties in producing threads inside the magnet and complex forms.
• Possible danger related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the context of child health protection. Furthermore, small elements of these products are able to disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

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

Information about lifting capacity is the result of a measurement for the most favorable conditions, assuming:

• on a plate made of mild steel, perfectly concentrating the magnetic field
• possessing a massiveness of minimum 10 mm to ensure full flux closure
• with a plane perfectly flat
• under conditions of no distance (surface-to-surface)
• during pulling in a direction vertical to the plane
• at standard ambient temperature

Determinants of practical lifting force of a magnet

It is worth knowing that the magnet holding may be lower influenced by elements below, in order of importance:

• Space between magnet and steel – every millimeter of separation (caused e.g. by varnish or dirt) drastically reduces the pulling force, often by half at just 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.
• Element thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the lifting capacity (the magnet "punches through" it).
• Metal type – not every steel attracts identically. Alloy additives weaken the interaction with the magnet.
• Smoothness – ideal contact is possible only on smooth steel. Rough texture reduce the real contact area, weakening the magnet.
• Thermal factor – hot environment weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the load capacity.