MW 6x6 / N38 - cylindrical magnet

Pros as well as cons of NdFeB magnets.

Apart from their strong magnetic energy, neodymium magnets have these key benefits:

• Their power remains stable, and after around ten years it decreases only by ~1% (theoretically),
• They possess excellent resistance to weakening of magnetic properties when exposed to opposing magnetic fields,
• By applying a shiny layer of gold, the element presents an professional look,
• Neodymium magnets create maximum magnetic induction on a contact point, which ensures high operational effectiveness,
• Through (adequate) combination of ingredients, they can achieve high thermal resistance, enabling action at temperatures reaching 230°C and above...
• Possibility of accurate machining as well as adapting to precise conditions,
• Significant place in advanced technology sectors – they are utilized in HDD drives, drive modules, advanced medical instruments, as well as modern systems.
• Thanks to their power density, small magnets offer high operating force, in miniature format,

Disadvantages of neodymium magnets:

• To avoid cracks upon strong impacts, we recommend using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
• When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power decreases (depending on the size, as well as 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 advise using water-impermeable magnets made of rubber, plastic or other material resistant to moisture
• Limited possibility of producing threads in the magnet and complicated forms - preferred is a housing - magnet mounting.
• Potential hazard related to microscopic parts of magnets pose a threat, when accidentally swallowed, which gains importance in the context of child health protection. It is also worth noting that tiny parts of these magnets are able to disrupt the diagnostic process medical in case of swallowing.
• High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which can limit application in large quantities

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

Holding force of 1.99 kg is a result of laboratory testing executed under standard conditions:

• on a base made of mild steel, effectively closing the magnetic flux
• possessing a massiveness of at least 10 mm to ensure full flux closure
• with an polished contact surface
• without any insulating layer between the magnet and steel
• during detachment in a direction perpendicular to the mounting surface
• at temperature approx. 20 degrees Celsius

Practical lifting capacity: influencing factors

Holding efficiency is affected by working environment parameters, mainly (from most important):

• Space between surfaces – every millimeter of separation (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
• Force direction – remember that the magnet has greatest strength perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the maximum value.
• Plate thickness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be wasted to the other side.
• Material type – ideal substrate is high-permeability steel. Hardened steels may have worse magnetic properties.
• Base smoothness – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
• Thermal factor – hot environment reduces magnetic field. Too high temperature can permanently damage the magnet.

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, in contrast under shearing force the lifting capacity is smaller. Moreover, even a small distance {between} the magnet’s surface and the plate reduces the holding force.