MP 30x6x10 / N38 - ring magnet

Pros and cons of rare earth magnets.

Besides their tremendous pulling force, neodymium magnets offer the following advantages:

• They do not lose power, even during approximately 10 years – the decrease in lifting capacity is only ~1% (theoretically),
• They do not lose their magnetic properties even under close interference source,
• A magnet with a shiny gold surface has an effective appearance,
• Magnets are characterized by exceptionally strong magnetic induction on the outer side,
• Neodymium magnets are known for strong magnetic induction and the ability to work at temperatures up to 230°C or higher (depending on the magnetic form),
• Thanks to flexibility in forming and the capacity to customize to complex applications,
• Versatile presence in electronics industry – they are utilized in HDD drives, drive modules, advanced medical instruments, and complex engineering applications.
• Compactness – despite small sizes they generate large force, making them ideal for precision applications

Disadvantages of NdFeB magnets:

• Susceptibility to cracking is one of their disadvantages. Upon strong impact they can break. We advise keeping them in a strong case, which not only secures them against impacts but also raises their durability
• When exposed to high temperature, neodymium magnets suffer a drop in strength. 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 - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• We suggest a housing - magnetic holder, due to difficulties in producing threads inside the magnet and complex shapes.
• Health risk related to microscopic parts of magnets can be dangerous, in case of ingestion, which is particularly important in the context of child health protection. It is also worth noting that small elements of these devices 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 hinders application in large quantities

Magnetic strength at its maximum – what affects it?

The load parameter shown represents the maximum value, obtained under laboratory conditions, namely:

• on a block made of structural steel, optimally conducting the magnetic flux
• whose thickness reaches at least 10 mm
• with an ground contact surface
• without any clearance between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at ambient temperature room level

Lifting capacity in real conditions – factors

Effective lifting capacity impacted by working environment parameters, including (from priority):

• Space between magnet and steel – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
• Pull-off angle – note that the magnet holds strongest perpendicularly. Under shear forces, the holding force drops drastically, often to levels of 20-30% of the nominal value.
• Element thickness – to utilize 100% power, the steel must be adequately massive. Thin sheet restricts the attraction force (the magnet "punches through" it).
• Chemical composition of the base – mild steel attracts best. Alloy admixtures lower magnetic properties and lifting capacity.
• Surface condition – ground elements ensure maximum contact, which increases force. Rough surfaces weaken the grip.
• Thermal environment – temperature increase causes a temporary drop of induction. It is worth remembering the maximum operating temperature for a given model.

* Holding force was tested on the plate surface of 20 mm thickness, when a perpendicular force was applied, whereas under shearing force the holding force is lower. Additionally, even a minimal clearance {between} the magnet and the plate reduces the holding force.