BM 450x180x70 [4x M8] - magnetic beam

Strengths and weaknesses of NdFeB magnets.

Besides their magnetic performance, neodymium magnets are valued for these benefits:

• They retain attractive force for nearly ten years – the loss is just ~1% (in theory),
• Neodymium magnets remain remarkably resistant to demagnetization caused by external field sources,
• The use of an elegant layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
• Neodymium magnets deliver maximum magnetic induction on a small area, which allows for strong attraction,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
• Possibility of custom shaping and adapting to specific applications,
• Universal use in innovative solutions – they find application in magnetic memories, electromotive mechanisms, medical equipment, as well as industrial machines.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Cons of neodymium magnets and proposals for their use:

• At very strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage and increases the magnet's durability.
• NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
• Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we suggest using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Due to limitations in producing threads and complex forms in magnets, we propose using cover - magnetic mechanism.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, tiny parts of these products are able to complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which can limit application in large quantities

Optimal lifting capacity of a neodymium magnet – what contributes to it?

Information about lifting capacity was determined for optimal configuration, assuming:

• on a plate made of structural steel, effectively closing the magnetic field
• possessing a thickness of at least 10 mm to ensure full flux closure
• characterized by even structure
• under conditions of no distance (surface-to-surface)
• during detachment in a direction perpendicular to the plane
• in temp. approx. 20°C

Practical lifting capacity: influencing factors

Please note that the working load will differ subject to the following factors, starting with the most relevant:

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or unevenness) drastically reduces the pulling force, often by half at just 0.5 mm.
• Loading method – catalog parameter refers to pulling vertically. When attempting to slide, the magnet exhibits much less (typically approx. 20-30% of nominal force).
• Metal thickness – thin material does not allow full use of the magnet. Magnetic flux penetrates through instead of generating force.
• Steel grade – the best choice is pure iron steel. Cast iron may have worse magnetic properties.
• Base smoothness – the more even the plate, the better the adhesion and stronger the hold. Roughness acts like micro-gaps.
• Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was carried out on plates with a smooth surface of suitable thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a minimal clearance {between} the magnet’s surface and the plate lowers the load capacity.