BM 750x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of rare earth magnets.

Besides their tremendous strength, neodymium magnets offer the following advantages:

• They do not lose power, even after around ten years – the decrease in power is only ~1% (theoretically),
• They have excellent resistance to weakening of magnetic properties when exposed to opposing magnetic fields,
• A magnet with a metallic silver surface looks better,
• They feature high magnetic induction at the operating surface, making them more effective,
• Through (appropriate) combination of ingredients, they can achieve high thermal strength, allowing for action at temperatures approaching 230°C and above...
• Possibility of exact modeling as well as modifying to precise needs,
• Huge importance in modern industrial fields – they are utilized in hard drives, motor assemblies, precision medical tools, 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: tips and applications.

• To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• NdFeB magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (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 extremely resistant to heat
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in realizing threads and complex shapes in magnets, we recommend using a housing - magnetic mount.
• Health risk related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the context of child safety. It is also worth noting that small components of these magnets are able to be problematic in diagnostics medical in case of swallowing.
• Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what it depends on?

The declared magnet strength concerns the limit force, measured under ideal test conditions, meaning:

• with the use of a sheet made of special test steel, guaranteeing full magnetic saturation
• with a cross-section of at least 10 mm
• with a surface perfectly flat
• with zero gap (without coatings)
• under perpendicular force direction (90-degree angle)
• at temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

In practice, the real power is determined by many variables, listed from crucial:

• Gap (betwixt the magnet and the metal), since even a microscopic distance (e.g. 0.5 mm) can cause a reduction in lifting capacity by up to 50% (this also applies to paint, corrosion or dirt).
• Force direction – catalog parameter refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
• Substrate thickness – for full efficiency, the steel must be adequately massive. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Steel grade – the best choice is high-permeability steel. Stainless steels may attract less.
• Smoothness – full contact is obtained only on smooth steel. Rough texture create air cushions, weakening the magnet.
• Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures gain strength (up to a certain limit).

* Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, in contrast under shearing force the load capacity is reduced by as much as 75%. Additionally, even a minimal clearance {between} the magnet’s surface and the plate reduces the load capacity.