BM 550x180x70 [4x M8] - magnetic beam

Pros as well as cons of rare earth magnets.

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

• They have constant strength, and over around ten years their performance decreases symbolically – ~1% (according to theory),
• They show high resistance to demagnetization induced by presence of other magnetic fields,
• By applying a reflective layer of gold, the element has an modern look,
• Magnetic induction on the top side of the magnet turns out to be maximum,
• Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
• Possibility of accurate shaping and adapting to specific conditions,
• Versatile presence in innovative solutions – they are used in HDD drives, electric motors, precision medical tools, also modern systems.
• Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which allows their use in compact constructions

Disadvantages of NdFeB magnets:

• Brittleness is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a steel housing, which not only secures them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their strength 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
• They oxidize in a humid environment. For use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Due to limitations in creating threads and complicated shapes in magnets, we propose using casing - magnetic mount.
• Possible danger 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 products are able to complicate diagnosis medical in case of swallowing.
• Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Maximum lifting force for a neodymium magnet – what it depends on?

Magnet power was determined for the most favorable conditions, assuming:

• on a plate made of mild steel, perfectly concentrating the magnetic flux
• with a cross-section no less than 10 mm
• characterized by lack of roughness
• without any clearance between the magnet and steel
• during detachment in a direction vertical to the plane
• at ambient temperature approx. 20 degrees Celsius

Determinants of practical lifting force of a magnet

Real force impacted by working environment parameters, including (from priority):

• Air gap (between the magnet and the metal), since even a tiny clearance (e.g. 0.5 mm) leads to a drastic drop in force by up to 50% (this also applies to varnish, corrosion or debris).
• Force direction – catalog parameter refers to pulling vertically. When slipping, the magnet exhibits much less (often approx. 20-30% of nominal force).
• Substrate thickness – for full efficiency, the steel must be sufficiently thick. Thin sheet restricts the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – low-carbon steel attracts best. Higher carbon content decrease magnetic properties and lifting capacity.
• Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces reduce efficiency.
• Temperature influence – high temperature reduces pulling force. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity testing was conducted on a smooth plate of optimal thickness, under a perpendicular pulling force, in contrast under attempts to slide the magnet the lifting capacity is smaller. Additionally, even a small distance {between} the magnet’s surface and the plate decreases the holding force.