BM 650x180x70 [4x M8] - magnetic beam

Strengths as well as weaknesses of neodymium magnets.

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

• They have stable power, and over more than 10 years their performance decreases symbolically – ~1% (in testing),
• Magnets effectively defend themselves against demagnetization caused by external fields,
• By covering with a decorative coating of silver, the element gains an nice look,
• Magnets possess exceptionally strong magnetic induction on the working 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 custom machining as well as adapting to complex conditions,
• Wide application in electronics industry – they are used in HDD drives, brushless drives, advanced medical instruments, and other advanced devices.
• Thanks to their power density, small magnets offer high operating force, with minimal size,

Disadvantages of NdFeB magnets:

• To avoid cracks under impact, we suggest using special steel holders. Such a solution secures the magnet and simultaneously improves its durability.
• We warn that neodymium magnets can reduce their power at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• When exposed to humidity, magnets usually rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which prevent oxidation as well as corrosion.
• Due to limitations in realizing threads and complicated forms in magnets, we propose using casing - magnetic mount.
• Potential hazard resulting from small fragments of magnets can be dangerous, if swallowed, which becomes key in the aspect of protecting the youngest. Additionally, small components of these magnets are able to complicate diagnosis medical when they are in the body.
• High unit price – neodymium magnets are more expensive than other types of magnets (e.g. ferrite), which increases costs of application in large quantities

Maximum holding power of the magnet – what it depends on?

The load parameter shown refers to the peak performance, recorded under laboratory conditions, meaning:

• using a base made of mild steel, functioning as a magnetic yoke
• with a thickness no less than 10 mm
• characterized by lack of roughness
• without the slightest air gap between the magnet and steel
• under vertical force direction (90-degree angle)
• in stable room temperature

Magnet lifting force in use – key factors

Bear in mind that the application force may be lower influenced by elements below, in order of importance:

• Air gap (between the magnet and the metal), since even a very small distance (e.g. 0.5 mm) results in a decrease in force by up to 50% (this also applies to paint, rust or dirt).
• Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the nominal value.
• Substrate thickness – to utilize 100% power, the steel must be adequately massive. Paper-thin metal restricts the lifting capacity (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Higher carbon content decrease magnetic permeability and holding force.
• Plate texture – ground elements ensure maximum contact, which increases force. Uneven metal weaken the grip.
• Operating temperature – NdFeB sinters have a negative temperature coefficient. When it is hot they lose power, and in frost gain strength (up to a certain limit).

* Lifting capacity was assessed by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular detachment force, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate reduces the holding force.