UMH 60x15x69 [M8] / N38 - magnetic holder with hook

Advantages as well as disadvantages of rare earth magnets.

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

• They have constant strength, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Neodymium magnets are distinguished by remarkably resistant to magnetic field loss caused by external field sources,
• The use of an metallic coating of noble metals (nickel, gold, silver) causes the element to look better,
• They show high magnetic induction at the operating surface, which affects their effectiveness,
• Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
• Thanks to the potential of free molding and customization to unique needs, NdFeB magnets can be created in a broad palette of shapes and sizes, which amplifies use scope,
• Wide application in modern industrial fields – they serve a role in mass storage devices, drive modules, medical devices, as well as complex engineering applications.
• Thanks to concentrated force, small magnets offer high operating force, in miniature format,

What to avoid - cons of neodymium magnets: application proposals

• To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution secures the magnet and simultaneously increases its durability.
• We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
• They rust in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
• Limited ability of producing threads in the magnet and complex shapes - preferred is a housing - magnetic holder.
• Health risk resulting from small fragments of magnets are risky, if swallowed, which is particularly important in the context of child safety. Additionally, small components of these devices are able to complicate diagnosis medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Detachment force of the magnet in optimal conditions – what affects it?

The declared magnet strength concerns the peak performance, recorded under ideal test conditions, meaning:

• on a plate made of mild steel, perfectly concentrating the magnetic field
• possessing a thickness of at least 10 mm to ensure full flux closure
• with a surface free of scratches
• with zero gap (no paint)
• during detachment in a direction vertical to the mounting surface
• at ambient temperature room level

Magnet lifting force in use – key factors

During everyday use, the actual holding force is determined by many variables, ranked from crucial:

• Clearance – existence of any layer (rust, dirt, gap) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops drastically, 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 limits the lifting capacity (the magnet "punches through" it).
• Material composition – different alloys reacts the same. High carbon content weaken the attraction effect.
• Plate texture – smooth surfaces ensure maximum contact, which increases force. Rough surfaces reduce efficiency.
• Operating temperature – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the lifting capacity is smaller. In addition, even a small distance {between} the magnet and the plate decreases the lifting capacity.