BM 450x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of rare earth magnets.

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

• Their power is maintained, and after around ten years it drops only by ~1% (according to research),
• Neodymium magnets are exceptionally resistant to magnetic field loss caused by magnetic disturbances,
• Thanks to the metallic finish, the surface of Ni-Cu-Ni, gold, or silver gives an aesthetic appearance,
• Neodymium magnets deliver maximum magnetic induction on a small surface, which increases force concentration,
• Thanks to resistance to high temperature, they are capable of working (depending on the shape) even at temperatures up to 230°C and higher...
• Possibility of exact shaping and optimizing to individual conditions,
• Significant place in electronics industry – they are utilized in magnetic memories, brushless drives, diagnostic systems, as well as industrial machines.
• Thanks to efficiency per cm³, small magnets offer high operating force, in miniature format,

Characteristics of disadvantages of neodymium magnets: application proposals

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a special holder, which not only secures them against impacts but also increases their durability
• 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 durability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore during using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of creating nuts in the magnet and complex forms - preferred is a housing - magnetic holder.
• Potential hazard resulting from small fragments of magnets pose a threat, if swallowed, which becomes key in the context of child health protection. Furthermore, tiny parts of these devices are able to complicate diagnosis medical in case of swallowing.
• Due to neodymium price, their price is relatively high,

Optimal lifting capacity of a neodymium magnet – what affects it?

Breakaway force was defined for the most favorable conditions, including:

• on a base made of mild steel, optimally conducting the magnetic field
• whose transverse dimension reaches at least 10 mm
• characterized by smoothness
• with total lack of distance (without paint)
• for force acting at a right angle (pull-off, not shear)
• in stable room temperature

Determinants of practical lifting force of a magnet

During everyday use, the actual holding force depends on a number of factors, ranked from most significant:

• Gap between surfaces – even a fraction of a millimeter of separation (caused e.g. by veneer or dirt) diminishes 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 significantly lower power (often approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick plate causes magnetic saturation, causing part of the power to be escaped to the other side.
• Steel type – low-carbon steel attracts best. Higher carbon content lower magnetic permeability and holding force.
• Surface condition – ground elements guarantee perfect abutment, which improves force. Uneven metal reduce efficiency.
• Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under perpendicular forces, whereas under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet’s surface and the plate decreases the holding force.