BM 550x180x70 [4x M8] - magnetic beam

Advantages as well as disadvantages of neodymium magnets.

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:

• They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (according to literature),
• Neodymium magnets remain extremely resistant to demagnetization caused by external field sources,
• In other words, due to the reflective layer of silver, the element is aesthetically pleasing,
• Magnets are distinguished by extremely high magnetic induction on the active area,
• Thanks to resistance to high temperature, they are capable of working (depending on the form) even at temperatures up to 230°C and higher...
• Possibility of custom machining as well as optimizing to defined applications,
• Wide application in modern technologies – they find application in magnetic memories, drive modules, advanced medical instruments, as well as modern systems.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

What to avoid - cons of neodymium magnets and proposals for their use:

• They are prone to damage upon heavy impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only protects the magnet but also increases its resistance to damage
• NdFeB magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
• 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
• We recommend a housing - magnetic mechanism, due to difficulties in creating threads inside the magnet and complex forms.
• Potential hazard related to microscopic parts of magnets can be dangerous, when accidentally swallowed, which is particularly important in the context of child health protection. It is also worth noting that small components of these devices can complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

Magnet power was determined for optimal configuration, taking into account:

• using a plate made of high-permeability steel, acting as a magnetic yoke
• with a thickness of at least 10 mm
• characterized by smoothness
• without any air gap between the magnet and steel
• during pulling in a direction perpendicular to the plane
• at ambient temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

Holding efficiency impacted by specific conditions, including (from most important):

• Distance – existence of foreign body (rust, dirt, air) interrupts the magnetic circuit, which reduces power steeply (even by 50% at 0.5 mm).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet holds significantly lower power (often approx. 20-30% of nominal force).
• Plate thickness – insufficiently thick plate does not close the flux, causing part of the flux to be wasted into the air.
• Material type – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
• Smoothness – full contact is possible only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Thermal factor – high temperature reduces magnetic field. Exceeding the limit temperature can permanently damage the magnet.

* Lifting capacity testing was performed on a smooth plate of suitable thickness, under a perpendicular pulling force, whereas under attempts to slide the magnet the load capacity is reduced by as much as fivefold. In addition, even a minimal clearance {between} the magnet’s surface and the plate reduces the lifting capacity.