NCM 30x13.5x5 / N38 - channel magnetic holder

Strengths as well as weaknesses of NdFeB magnets.

In addition to their magnetic capacity, neodymium magnets provide the following advantages:

• They virtually do not lose strength, because even after ten years the performance loss is only ~1% (in laboratory conditions),
• They are noted for resistance to demagnetization induced by external disturbances,
• Thanks to the smooth finish, the surface of Ni-Cu-Ni, gold-plated, or silver-plated gives an elegant appearance,
• Magnetic induction on the working layer of the magnet is strong,
• Due to their durability and thermal resistance, neodymium magnets can operate (depending on the form) even at high temperatures reaching 230°C or more...
• Thanks to the possibility of flexible shaping and adaptation to specialized requirements, magnetic components can be manufactured in a variety of shapes and sizes, which increases their versatility,
• Key role in advanced technology sectors – they are utilized in HDD drives, electric motors, precision medical tools, and modern systems.
• Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Disadvantages of neodymium magnets:

• They are fragile upon too strong impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only shields the magnet but also increases its resistance to damage
• Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
• They rust in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
• Limited possibility of producing nuts in the magnet and complex shapes - recommended is cover - mounting mechanism.
• Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which becomes key in the context of child health protection. Furthermore, small components of these products 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

Highest magnetic holding force – what affects it?

The load parameter shown concerns the maximum value, recorded under optimal environment, specifically:

• using a sheet made of high-permeability steel, functioning as a circuit closing element
• with a thickness minimum 10 mm
• characterized by smoothness
• without any air gap between the magnet and steel
• for force applied at a right angle (pull-off, not shear)
• at temperature approx. 20 degrees Celsius

Lifting capacity in practice – influencing factors

In real-world applications, the actual lifting capacity depends on a number of factors, ranked from crucial:

• Clearance – existence of any layer (paint, dirt, air) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
• Loading method – catalog parameter refers to detachment vertically. When slipping, the magnet exhibits significantly lower power (often approx. 20-30% of nominal force).
• Wall thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of generating force.
• Steel grade – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
• Smoothness – ideal contact is possible only on smooth steel. Rough texture reduce the real contact area, reducing force.
• Temperature – heating the magnet results in weakening of induction. It is worth remembering the thermal limit for a given model.

* Lifting capacity was assessed with the use of a smooth steel plate of suitable thickness (min. 20 mm), under vertically applied force, whereas under parallel forces the load capacity is reduced by as much as fivefold. Additionally, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.