BM 950x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of rare earth magnets.

Apart from their superior holding force, neodymium magnets have these key benefits:

• They have constant strength, and over around ten years their attraction force decreases symbolically – ~1% (in testing),
• They retain their magnetic properties even under close interference source,
• By covering with a lustrous coating of gold, the element acquires an modern look,
• Magnets are distinguished by exceptionally strong magnetic induction on the surface,
• Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
• Possibility of individual forming and adjusting to concrete conditions,
• Huge importance in high-tech industry – they are utilized in magnetic memories, electric drive systems, medical equipment, also modern systems.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Problematic aspects of neodymium magnets: application proposals

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
• When exposed to high temperature, neodymium magnets experience a drop in force. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
• Magnets exposed to a humid environment can corrode. Therefore during using outdoors, we suggest using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of creating threads in the magnet and complex shapes - preferred is a housing - magnetic holder.
• Health risk resulting from small fragments of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, tiny parts of these devices can 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

Breakaway strength of the magnet in ideal conditions – what contributes to it?

The declared magnet strength refers to the peak performance, obtained under optimal environment, specifically:

• with the use of a sheet made of special test steel, guaranteeing maximum field concentration
• whose thickness equals approx. 10 mm
• with an ideally smooth touching surface
• without the slightest air gap between the magnet and steel
• during pulling in a direction perpendicular to the mounting surface
• at room temperature

Impact of factors on magnetic holding capacity in practice

It is worth knowing that the magnet holding may be lower subject to the following factors, starting with the most relevant:

• Gap (betwixt the magnet and the plate), as even a microscopic clearance (e.g. 0.5 mm) can cause a drastic drop in lifting capacity by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – declared lifting capacity refers to pulling vertically. When slipping, the magnet holds significantly lower power (typically approx. 20-30% of nominal force).
• Steel thickness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be wasted to the other side.
• Metal type – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
• Surface finish – ideal contact is obtained only on smooth steel. Any scratches and bumps create air cushions, reducing force.
• Thermal environment – heating the magnet results in weakening of induction. Check the maximum operating temperature for a given model.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under shearing force the holding force is lower. Additionally, even a slight gap {between} the magnet and the plate lowers the load capacity.