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

Strengths and weaknesses of neodymium magnets.

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

• They have unchanged lifting capacity, and over around 10 years their attraction force decreases symbolically – ~1% (according to theory),
• Neodymium magnets are highly resistant to loss of magnetic properties caused by external magnetic fields,
• In other words, due to the reflective layer of gold, the element gains visual value,
• Magnets have exceptionally strong magnetic induction on the outer layer,
• Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can function (depending on the shape) even at a temperature of 230°C or more...
• In view of the potential of precise shaping and customization to individualized needs, NdFeB magnets can be produced in a wide range of geometric configurations, which increases their versatility,
• Universal use in advanced technology sectors – they find application in magnetic memories, electromotive mechanisms, precision medical tools, also other advanced devices.
• Thanks to efficiency per cm³, small magnets offer high operating force, occupying minimum space,

Disadvantages of neodymium magnets:

• At very strong impacts they can crack, therefore we advise placing them in strong housings. A metal housing provides additional protection against damage and increases the magnet's durability.
• Neodymium magnets lose their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
• Due to the susceptibility of magnets to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
• We suggest cover - magnetic holder, due to difficulties in producing threads inside the magnet and complex shapes.
• Potential hazard related to microscopic parts of magnets are risky, in case of ingestion, which becomes key in the context of child safety. Furthermore, small elements of these devices can be problematic in diagnostics medical after entering the body.
• High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Maximum holding power of the magnet – what contributes to it?

Breakaway force is the result of a measurement for the most favorable conditions, taking into account:

• using a plate made of low-carbon steel, functioning as a circuit closing element
• possessing a massiveness of minimum 10 mm to avoid saturation
• with a plane perfectly flat
• without the slightest clearance between the magnet and steel
• for force applied at a right angle (in the magnet axis)
• at conditions approx. 20°C

Magnet lifting force in use – key factors

Please note that the magnet holding may be lower influenced by the following factors, starting with the most relevant:

• Air gap (between the magnet and the metal), as even a very small clearance (e.g. 0.5 mm) leads to a drastic drop in lifting capacity by up to 50% (this also applies to paint, rust or debris).
• Pull-off angle – note that the magnet has greatest strength perpendicularly. Under sliding down, the capacity drops significantly, often to levels of 20-30% of the nominal value.
• Substrate thickness – for full efficiency, the steel must be adequately massive. Paper-thin metal limits the attraction force (the magnet "punches through" it).
• Steel grade – the best choice is pure iron steel. Stainless steels may generate lower lifting capacity.
• Surface condition – smooth surfaces guarantee perfect abutment, which improves force. Uneven metal weaken the grip.
• Temperature influence – high temperature reduces magnetic field. Too high temperature can permanently demagnetize the magnet.

* Lifting capacity was assessed with the use of a polished steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.