BM 450x180x70 [4x M8] - magnetic beam

Advantages and disadvantages of rare earth magnets.

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

• They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (based on calculations),
• They retain their magnetic properties even under close interference source,
• By applying a reflective coating of silver, the element gains an elegant look,
• Neodymium magnets deliver maximum magnetic induction on a small surface, which increases force concentration,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to the ability of free molding and adaptation to custom solutions, neodymium magnets can be produced in a wide range of shapes and sizes, which amplifies use scope,
• Key role in modern industrial fields – they find application in hard drives, electromotive mechanisms, precision medical tools, also modern systems.
• Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Problematic aspects of neodymium magnets and proposals for their use:

• At strong impacts they can crack, therefore we recommend placing them in steel cases. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Magnets exposed to a humid environment can rust. Therefore when using outdoors, we advise using waterproof magnets made of rubber, plastic or other material protecting against moisture
• Limited possibility of making nuts in the magnet and complex shapes - recommended is a housing - magnet mounting.
• Potential hazard related to microscopic parts of magnets are risky, if swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, tiny parts of these magnets are able to disrupt the diagnostic process medical after entering the body.
• With large orders the cost of neodymium magnets is a challenge,

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

Magnet power was defined for ideal contact conditions, assuming:

• on a base made of mild steel, perfectly concentrating the magnetic field
• whose thickness is min. 10 mm
• with a surface free of scratches
• without any air gap between the magnet and steel
• during pulling in a direction vertical to the plane
• at temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

Bear in mind that the magnet holding may be lower influenced by the following factors, starting with the most relevant:

• Distance – existence of foreign body (rust, dirt, gap) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Force direction – catalog parameter refers to pulling vertically. When attempting to slide, the magnet holds much less (often approx. 20-30% of maximum force).
• Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field passes through the material instead of generating force.
• Material type – the best choice is pure iron steel. Hardened steels may generate lower lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Uneven metal weaken the grip.
• Thermal factor – hot environment weakens magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a minimal clearance {between} the magnet’s surface and the plate decreases the holding force.