BM 950x180x70 [4x M8] - magnetic beam

Pros as well as cons of rare earth magnets.

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

• They do not lose magnetism, even after nearly 10 years – the reduction in power is only ~1% (based on measurements),
• They are extremely resistant to demagnetization induced by external magnetic fields,
• A magnet with a shiny silver surface has better aesthetics,
• Magnets have exceptionally strong magnetic induction on the surface,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, allowing for action at temperatures approaching 230°C and above...
• Thanks to versatility in designing and the capacity to modify to unusual requirements,
• Huge importance in electronics industry – they are utilized in magnetic memories, motor assemblies, precision medical tools, also other advanced devices.
• Relatively small size with high pulling force – neodymium magnets offer high power in tiny dimensions, which enables their usage in small systems

Disadvantages of neodymium magnets:

• At strong impacts they can crack, therefore we recommend placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
• We recommend casing - magnetic holder, due to difficulties in creating nuts inside the magnet and complex shapes.
• Health risk resulting from small fragments of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Additionally, small elements of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• Due to complex production process, their price exceeds standard values,

Maximum lifting force for a neodymium magnet – what affects it?

The declared magnet strength refers to the maximum value, measured under optimal environment, specifically:

• with the use of a yoke made of special test steel, ensuring maximum field concentration
• whose transverse dimension reaches at least 10 mm
• with a surface free of scratches
• without the slightest clearance between the magnet and steel
• 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 real power results from several key aspects, presented from crucial:

• Gap between surfaces – every 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 slipping, the magnet holds much less (often approx. 20-30% of nominal force).
• Base massiveness – insufficiently thick sheet causes magnetic saturation, causing part of the flux to be lost into the air.
• Steel grade – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
• Plate texture – ground elements ensure maximum contact, which improves force. Rough surfaces reduce efficiency.
• Thermal environment – heating the magnet results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was measured on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet and the plate reduces the holding force.